A group of researchers at Carnegie Mellon University is trying to get a better understanding of the views of earth scientists regarding various climate change topics. They have set up an ongoing poll to do this, called Vision Prize. It’s a short (10 question) poll, covering topics like the rate of CO2 increase, predicted future temperatures, sea ice and sea level states, and hurricane frequencies. Early participants can designate a $20 donation from the group to a charity of their choice, upon completion. Please take a few minutes to help them out if qualified.

This article was originally posted on Real Climate

by Nick Sundt, reposted from the World Wildlife Fund

This article was originally posted on Climate Progress

by Kevin Benfield, cross-posted from NRDC’s Switchboard

When you look at the official US drought monitor map, you immediately see that many American cities may be in the wrong places for long-term water sustainability.  In particullar, note the presence of “long-term,” severe-to-extreme drought conditions across most of Georgia, Texas, Oklahoma, New Mexico, and Arizona.

It’s a very sobering set of facts, especially when you consider that essentially every high-growth part of the US is experiencing significant dryness.  Now let’s look at a second map, this time world-wide:

This is not just a US Sun Belt problem but a major international problem.  Here are a few facts and projections extracted from a very good summary of the issues by Jay Kimball on his blog 8020 Vision:

• By 2020, California will face a shortfall of fresh water as great as the amount that all of its cities and towns together are consuming today.
• By 2025, 1.8 billion people will live in conditions of absolute
 water scarcity, and 65 percent of the world’s population will be water stressed.
• In the US, 21 percent of agricultural irrigation is achieved by pumping groundwater at rates that exceed the water supplies ability to recharge.
• There are 66 golf courses in Palm Springs. On average, they each consume over a million gallons of water per day.
• The Ogalala aquifer, which stretches across 8 states and accounts for 40 percent of water used in Texas, will decline in volume by a staggering 52 percent between 2010 and 2060.
• Texans are probably pumping the Ogallala at about six times the rate of recharge.

With increasing rises in the temperature of the earth’s surface and atmosphere, this problem seems only likely to get worse.  The geographic details may shift from one season to another, but the long-range trend is toward further diminishing of our sources of water.  A major problem with so many environmental issues, including this one, is that the damage occurs slowly, so that people are lulled into gradually accepting additional increments of deteriorating conditions without alarm.  But that doesn’t change the facts.

Looking at the US, we’re not realistically going to shut down the whole state of Texas, along with Atlanta, Oklahoma City, Albuquerque and Phoenix.  We’re not going to stop those places from growing, either, pipe dreams of some ardent environmentalists aside.  (Nor are we going to shut down North Africa, every country bordering the Mediterranean, India, and large parts of China.)

So, what to do?

This is not going to be a post that pretends to have all the answers, many of which are going to have to come from agriculture, which is outside my expertise.  But I’ll offer a few thoughts about some answers that must also come from how we grow our cities.

For example, a decade ago, my colleague Deron Lovaas co-authored a report demonstrating how the spread of pavement caused by suburban sprawl prevents water from recharging underground reserves.  From a summary released by NRDC with its research partners American Rivers and Smart Growth America:

“In Atlanta, the nation’s most rapidly sprawling metropolitan area, recent sprawl development sends an additional 57 billion to 133 billion gallons of polluted runoff into streams and rivers each year. This water would have otherwise filtered through the soil to recharge aquifers and provide underground flows to rivers, streams and lakes.”

EPA research shows that building 1000 new homes in a watershed at an average density of eight units per acre instead of four units per acre could save as much as 27 million cubic feet of runoff per year in a typical watershed.  (Building at eight units per acre instead of one unit per acre could save 137 cubic feet of runoff per year.)

Greater average density also means less irrigated urban land per household.

In addition, I’ve been arguing for some time that “green buildings” aren’t really green if they contribute to sprawl, and that “smart growth” isn’t really smart unless it includes green buildings and infrastructure.  Doesn’t the presence of long-term drought conditions argue even more strongly for the notion that smart growth should include water-efficient technology and green infrastructure to filter rainwater before it becomes runoff?

Finally, could this be another argument in favor of reviving, rather than abandoning, our Rust Belt cities in order to take growth pressure off the Sun Belt?

– Kaid Benfield writes (almost) daily about community, development, and the environment.  For more posts, see his blog’s home page. Please also visit NRDC’s Sustainable Communities Video Channel.

This article was originally posted on Climate Progress

So what, other than bad journalism, explains this nonsensical headline and image from the top tech magazine Wired?

Actually, it is just bad journalism, pure and simple.  Indeed, the magazine itself clearly wanted a sensationalistic headline — and even more sensationalistic photo — to get eyeballs in this highly competitive media environment.

The story simply doesn’t justify the headline. That’s obvious from the fact that the story itself includes this summary of wind energy prospects:

Outlook: Cheaper prices for turbines should result in lower costs for wind power by 2014. Though growth has slowed since 2008, this sector is still expected to cover about a third of any increased energy consumption in the US between now and 2035.

Huh?  An energy industry that barely registered any significant U.S. capacity or generation a decade ago is now  expected to provide a third of the increased energy consumption in the next quarter century — and that’s somehow a clean-tech “bust” which warrants an exploding wind-turbine image?  Amazing (and I will repost a response to the article by a leading wind expert below).

For the record, I’m not saying the wind industry doesn’t face a near-term challenge in the face of unconventional gas and a GOP Congress unwilling to support a crucial tax credit.  Climate Progress has made clear that it does (see “Policy Uncertainty Threatens 1,600 American Wind Jobs at Vestas — and 37,000 Jobs Nationwide“).  I’m saying that there has been no bust in the industry yet, there doesn’t need to be one, and, indeed, the prospects  for the industry over the next couple of decades remain very strong, as the article itself makes clear.

I asked Eilperin about the headline and images, which I thought were completely unwarranted.  She makes clear she had nothing to do with them:

“I stand by the story, which accurately portrays some of the challenges the U.S. clean tech faces in light of the current fiscal and political climate. The piece also highlight some of the industry’s bright spots, including the fact that cheaper conventional PV panels has made the expansion of distributed solar generation and utility-scale solar projects more affordable. As many magazine readers would understand, I had no input into either the display art or the headline that accompanied the piece.”

Readers know that headlines  are the most important part of any such story, seen by  at least 10 times as many people who read it — and in the internet era, it’s likely that 20 to 100 times as many people see the headline from a  respected magazine like Wired.

Wired should retract and change the headline.

I blame the editors for this — but I don’t agree with Eilperin’s assessment of the story itself.  I think it is flawed, especially its discussion of solar energy.

The piece uses Solyndra as a stand-in for the entire US solar industry and devotes over one third of the piece to the now-bankrupt company.  But Eilperin and Wired seem completely unaware of the fact that Solyndra was always a one-of-a-kind solar play that made sense only if silicon prices stayed high.  In that sense, it was obviously part of a ”portfolio” investment strategy by DOE, a hedge against their much broader strategy, which was based on silicon prices coming down.  As Bloomberg Government made  clear in a recent analysis that received virtually no coverage in the media, “the focus on Solyndra is not proportional to its impact.”  About 87% of the DOE loan portfolio is low-risk.

You’d never know from the Wired piece that in 2010, America was a net exporter of $1.9 billion in solar products.   You’d never know that the U.S. solar industry grew 100% in 2010 and another 100% in 2011, making  it perhaps the “fastest growing” industry in America.

How does Wired make the case that the solar industry is a bust when there are ”over 100,000 Americans are working in the solar Industry.”

Promise:  … In 2010, the solar industry predicted that as many as 500,000 people would be directly or indirectly employed in the US solar sector by 2016.

Reality: As we head into 2012, the number is more like 100,000. Prices for conventional solar cells have fallen 40 percent in the past year, due largely to a flood of panels from Chinese manufacturers, which have benefited from plunging silicon prices and government support. The price drop has eviscerated the US solar manufacturing industry.

Seriously.  Apparently because there is one solar study that said we would have 500,000 jobs 4 years from now, the super-fast growing industry with 100,000 jobs is a bust.  For the record:

• It is a 2011 study .
• The 500,000 number assumes a 5-year extension of the crucial Treasury Grant Program.
• The 500,000 number is based on direct, indirect and induced jobs. Induced jobs roughly double the total!

Yet Wired still had the chutzpah  to use this image as its depiction of this staggeringly successful American industry:

Wired Caption:  ”Solar: Cheap panels from China have viscerated the US industry.”

No, the industry isn’t quite yet disemboweled.  Again, one part of the U.S. industry — manufacturing of solar cells — certainly faces a great challenge from China.

But the article  is quite confused about the impact of shale gas on solar, asserting:

Meanwhile the price of natural gas has fallen by 77 percent since 2008, and the cost of producing electricity in gas plants is down 40 percent since then. Renewables simply can’t compete.

In the case of solar, the article  utterly misses the key point that solar photovoltaics generally compete with the retail price of power, not the wholesale price.

I asked one of the leading experts on solar energy, Jigar Shah, for a response.  Shah, who founded the pioneering solar company SunEdison, writes me:

Since 2000, commercial electricity prices have gone up by almost 5% per year.  Even after the crash in wholesale prices from the financial crisis of 2008, most electricity customers are still paying much higher prices than the historic 0.6% annual rate increases in the 1980s and 90s.  The reason for this is that all of the infrastructure in the United States is “old”.  Most of the coal plants are over 40 years old and realistically cannot be run for more than another 10 to 20 years.  Most of the substations in the United States were built before everyone decided to install air conditioning.  When new natural gas plants are built, it isn’t the gas plant that is so expensive, it is the changes in the grid required to accept this new concentrated electricity source that makes up the bulk of the expenses.

With installed solar prices approaching the $2/Wdc mark for commercial rooftop systems, it is now more cost effective than retail electricity prices for over 20% of all US electricity covering 200 utilities in 29 states.  The persistence and the excitement fueled by the VC community caused over 5,000 contractors to invest their hard earned money to make solar in the local community a reality.  The final step in the solar transformation is about finance, not about technology.  In 2008, the solar industry was on the cusp of finally creating ways for common Americans to invest in solar power, to put their money where the poll numbers already suggest their heart is.  This last step was postponed by the financial crisis and is finally ready to be started again.  There are ten individual initiatives that are being led by entrepreneurs, well-known private equity managers, and large well capitalized companies all headed for the same objective, bring low risk solar assets to the public markets so that pension funds and individual investors can benefit from what Warren Buffet already knows — renewable energy projects have a higher yield and are a safer investment than corporate bonds.

In the oil, electricity, and transportation industries we have annual capital expenditures into infrastructure (not consumer products) of almost $2 Trillion per year.  The combined revenues of HP, IBM, Cisco and others that sell hardware for information infrastructure is almost 10 times less than that.  Shifting the investment into our core energy infrastructure is a multi-decade struggle that has resulted in 2010 with more money going into new renewables of $187B  while only $157B went in to new fossil fuel and nuclear generation.  Given that investment banks, law firms, and jobs care about new stuff being built all shifted their loyalties to the renewables side of the ledger.  In 2011, Bloomberg New Energy Finance said that since 2000 we have invested over $1 Trillion in clean energy broadly — $243B in 2010 alone.  This means that with current growth rates, our next Trillion will take only 4 years and by 2020 we will probably be at $1 Trillion annually — over 50% of the almost $2 Trillion needed by the whole energy industry.

Financial innovation is about building trust.  Investors need to believe that these technologies have almost zero technology risk or 100,000 hours of field testing.  They need to know that the financial products are structured in a way that clearly takes into account all of the risks.  While these steps are easier for clean energy, they are not trivial.  The efforts of the VCs and the US Government mean that we now have a set of technologies that meet this profile and have been accepted by the grand masters of finance such that they can reach $1 Trillion of annual investment by 2020.  Like the oil and gas industry, more innovation will always be possible, but meeting the final hurdle of acceptance by the finance industry is something that the oil and gas industry knows how to do.  And now so do we.

So, no, the US solar industry has not busted yet, and the future  is incredibly bright.  Would it be even brighter if  Congress were willing to extend the tax credits?  Of course, but solar is here to stay in any case.

As for wind power, Tom Gray of the American Wind Energy Association posted this response [scroll to bottom] on Wired’s website :

1) Wind is close to cost-competitive with new natural gas generation, even at today’s unsustainably low natural gas prices, and has positive offsetting benefits.

Adding wind farms to a power system helps lower fuel prices and electric rates and make them more stable and predictable.  For example, the Colorado Public Utility Commission recently approved a 25-year, 200-megawatt (MW) power purchase agreement between Xcel Energy subsidiary Public Service Co. of Colorado and NextEra Energy for power from the Limon Wind 2 project. The Colorado PUC underscored how the contract would be cost effective for consumers, saying, “the contract will save ratepayers $100 million on a net-present-value basis over its 25-year term under a base-case natural gas price scenario.”

As Bloomberg New Energy Finance lead wind analyst Justin Wu recently commented, “The public perception of wind power tends to be that it is environmentally friendly, but expensive and intermittent. That is out of date in the best locations, where generation is already cost‐competitive with fossil fuel electricity, and that will be the case for the majority of new onshore turbines installed worldwide by 2016.”

2) States that rely more on wind power have seen their electricity rates rise more slowly than states with little or no wind.

According to the Energy Information Administration (EIA), the 40 states with least wind installed (and the District of Columbia) saw electric rates rise by just over 34% between 2005 and 2010.  By contrast, the top 10 states in wind generation (with wind providing between 5.1% and 15.4% of electricity) saw an increase of less than 11%, or less than one-third as much.

Electricity rates are the result of a number of factors, so wind can’t get all the credit.  However, it makes sense that a resource with zero fuel costs, when it is available, is going to push the most expensive (and dirtiest) power plants on a utility system off line and save consumers money.

[See "The 5 States With the Most Installed Wind and Solar Power Saw the Least Increase in Electricity Prices from 2005-2010."]

3) Rep. Stearns is misinformed.  Wind energy is an American manufacturing success story. The wind industry has been a bright spot through the depths of the recession, creating one of the fastest-growing U.S. manufacturing sectors. Wind is actually insourcing a whole new manufacturing sector. Sixty percent of a wind turbine’s value is now produced here in America, compared to 25% prior to 2005. As the nonpartisan Congressional Research Service recently found, American wind manufacturing facilities have grown to almost 400 in 2010, up from as few as 30 in 2004. The key to that expansion has been the federal Production Tax Credit for wind, which has helped the companies that build wind farms to attract investment and create a market for turbines.

A recent study from Navigant Consulting finds that with stable tax policy, the wind industry can grow to nearly 100,000 American jobs in the next four years, including growing the wind manufacturing sector by one third to 46,000 American manufacturing jobs. This will keep the wind sector on track toward supporting the 500,000 jobs by 2030 envisioned in a report by the U.S. Department of Energy during the George W. Bush administration.

The development of clean, renewable energy sources such as wind power is critically important for the future of the country and everyone who uses electricity now and in the future. Wind energy is clean, abundant, and homegrown, and its cost is dropping. The case for continuing to invest in its growth through a reasonable low tax rate remains strong. And to change course now would only shut down a new U.S. manufacturing sector, just as it is starting to deliver on a large scale.

Let wind finish the job. – Tom Gray, American Wind Energy Association

So, no, there hasn’t been a bust in clean tech yet, and the industry is poised to do unbelievably well in the coming decades.  Yes, the foes of clean energy in Congress can put a crimp in the near-term growth, but the technological and marketplace reality is  very promising for renewables in the medium term.  And, of course, the ever accelerating reality of climate change means renewables are the inevitable winner in the longer term, no matter how hard their  opponents try to kill the US industry.

This article was originally posted on Climate Progress

by Dana Nuccitelli

At Skeptical Science, we have several recent studies which have used a number of diverse approaches to tease out the contributions of various natural and human effects to global warming.  Here we will review the results of these various studies, and a few others which we have not previously examined, to see what the scientific literature and data have to say about exactly what is causing global warming.

All of these studies, using a wide range of independent methods, provide multiple lines of evidence that humans are the dominant cause of global warming over the past century, and especially over the past 50 to 65 years (Figure 1).

Figure 1: Net human and natural percent contributions to the observed global surface warming over the past 50-65 years according to Tett et al. 2000 (T00, dark blue), Meehl et al. 2004 (M04, red), Stone et al. 2007 (S07, green), Lean and Rind 2008 (LR08, purple), Huber and Knutti 2011 (HK11, light blue), and Gillett et al. 2012 (G12, orange).  This has been added to the SkS Climate Graphics Page.

Note that the numbers provided in this summary post are best estimates from each paper.  For the sake of simplicity we have not included error bars, but we have provided links to the original research for those who would like to see the uncertainty ranges in each estimate.

A Quick Look at the Various Effects on Global Temperature

Most of the studies discussed below looked at the same few influences on global temperature, because they are the dominant effects.

As we know, human greenhouse gas (GHG) emissions warm the planet by increasing the abundance of greenhouse gases in the atmosphere, thus increasing the greenhouse effect.

Solar activity also warms or cools the planet by increasing or decreasing the amount of radiation reaching the Earth’s atmosphere and surface.

Volcanic activity generally cools the planet over short timeframes by releasing sulfate aerosols into the atmosphere, which block sunlight and reduce the amout of solar radiation reaching the surface.  However, unlike many greenhouse gases, aerosols are washed out of the atmosphere quickly, mostly after just 1-2 years.  Thus the main volcanic impact on long-term temperature changes occur when there is an extended period of particularly high or low volcanic activity.

Human aerosol emissions (primarily sulfur dioxide [SO2]) also tend to cool the planet.  The main difference is that unlike volcanoes, humans are constantly pumping large quantities of aerosols in the atmosphere by burning fossil fuels and biomatter.  This allows human aerosol emissions to have a long-term impact on temperatures, as long as we keep burning these fuels.  However, because aerosols have a number of different effects (including directly by blocking sunlight, and indirectly by seeding clouds, which both block sunlight and increase the greenhouse effect), the magnitude of their cooling effect is one of the biggest remaining uncertainties in climate science.

The El Niño Southern Oscillation (ENSO) is an oceanic cycle which alternates between El Niño and La Niña phases.  El Niño tends to shift heat from the oceans to the air, causing surface warming (but ocean cooling), whereas La Niña acts in the opposite manner.  As we’ll see, a few studies have begun examining whether ENSO has had a long-term impact on global surface temperatures.  Because it’s a cycle/oscillation, it tends to have little impact on long-term temperature changes, with the effects of La Niña cancelling out those of El Niño.

There are other effects, but GHGs and SO2 are the two largest human influences, and solar and volcanic activity and ENSO are the dominant natural influences on global temperature.  Now let’s see what the scientific literature has to say about the relative influences of each effect.

Tett et al. (2000)

Tett et al. (2000) used an “optical detection methodology” with global climate model simulations to try and match the observational data.  The inputs into the model included measurements of GHGs in the atmosphere, aerosols from volcanic eruptions, solar irradiance, human aerosol emissions, and atmospheric ozone changes (ozone is another greenhouse gas).

Tett et al. applied their model to global surface temperatures from 1897 to 1997.  Their best estimate matched the overall global warming during this period very well; however, it underestimated the warming from 1897 to 1947, and overestimated the warming from 1947 to 1997.  For this reason, during the most recent 50 year period in their study (shown in dark blue in Figure 1), the sum of their natural and human global warming contributions is larger than 100%, since their model shows more warming than observed over that period.  Over both the 50 and 100 year timeframes, Tett et al. estimated that natural factors have had a slight net cooling effect, and thus human factors have caused more than 100% of the observed global warming.

Meehl et al. (2004)

Meehl et al. 2004 used a similar approach to Tett et al., running global climate model simulations using various combinations of the different main factors which influence global temperatures (GHGs, solar activity, volcanic aerosols, human aerosols, and ozone), and comparing the results to the temperature data from 1890 to 2000.  They found that natural factors could account for most of the warming from 1910 to 1940, but simply could not account for the global warming we’ve experienced since the mid-20th Century.

Meehl et al. estimated that approximately 80% of the global warming from 1890 to 2000 was due to human effects.  Over the most recent 50 years in their study (1950-2000), natural effects combined for a net cooling, and thus like Tett et al., Meehl et al. concluded that human caused more than 100% of the global warming over that period.  Over the past 25 years, nearly 100% of the warming is due to humans, in their estimate.

Stone et al. (2007)

Stone et al. actually published two studies in 2007.  The first paper examined a set of 62 climate model simulation runs for the time period of 1940 to 2080 (the Dutch Meteorological Institute’s “Challenge Project”).  These simulations utilized measurements of GHGs, volcanic aerosols, human aerosols, and solar activity from 1940 to 2005, similar to the Tett and Meehl studies discussed above, and then used projected future emissions from the Intergovernmental Panel on Climate Change (IPCC) to project future global warming.  Whereas Tett and Meehl examined the climate response to each individual factor (and/or combinaton of factors), Stone compared these 62 climate model runs to a series of energy balance models, each representing the climate’s response to a different effect.  Over the 60 year period, Stone et al. estimated that humans caused close to 100% of the observed warming, and the natural factors had a net negative effect.  As with Stott, their model did not fit the data perfectly, though they had the opposite result, underestimating the observed warming.

In their second 2007 paper, Stone et al. updated the results from their first paper by including more climate models and more up-to-date data, and examining the timeframe of 1901 to 2005.  Over that full 104-year period, Stone et al. estimated that humans and natural effects had each contributed to approximately half of the observed warming.  Greenhouse gases contributed to 100% of the observed warming, but half of that effect was offset by the cooling effect of human aerosol emissions.  They estimated that solar and volcanic activity were responsible for 37% and 13% of the warming, respectively.

Lean and Rind (2008)

Lean and Rind 2008 used more of a statistical approach than these previous studies, using a multiple linear regression analysis.  In this approach, Lean and Rind used measurements of solar, volcanic, and human influences, as well as ENSO, and statistically matched them to the observational temperature data to achieve the best fit.  Analyzing what is left over after summing the various contributions shows whether the most significant contributions are being considered.

LR08 did this over various timeframes, and found that from 1889 to 2006, humans caused nearly 80% of the observed warming, versus approximately 12% from natural effects.  As with the previous studies discussed, this doesn’t add up to exactly 100% because the statistical fit is not perfect, and not every effect on global temperature was taken into consideration.  From both 1955 and 1979 to 2005, they estimated that humans have caused close to 100% of the observed warming.

Stott et al. (2010)

Stott et al. (S10) used a somewhat similar approach to LR08, but they used their statistical multiple linear regression results to constrain simulations from five different climate models.  S10 calculated regression coefficients for greenhouse gases, other human effects (dominated by aerosols), and natural effects (solar and volcanic), and estimated how much warming each caused over the 20th Century.  The average of the five models put the human contribution at 86% of the observed warming, and greenhouse gases at 138%, with a very small natural contribution.

Stott et al. also corrobarated their results by looking not only at global, but also regional climate changes by reviewing the body of scientific literature.  They note that human influences have been detected in changes in local temperatures, precipitation changes, atmospheric humidity, drought, Arctic ice decline, extreme heat events, ocean heat and salinity changes, and a number of other regional climate impacts.

Huber and Knutti (2011)

Huber and Knutti 2011 implemented a very interesting approach in their study, utilizing the principle of conservation of energy for the global energy budget to quantify the various contributions to the observed global warming from 1850 and 1950 to the 2000s.  Huber and Knutti took the estimated global heat content increase since 1850, calculated how much of the increase is due to various estimated radiative forcings, and partition the increase between increasing ocean heat content and outgoing longwave radiation.  More than 85% of the global heat uptake has gone into the oceans, so by including this data, their study is particularly robust.

Huber and Knutti estimate that since 1850 and 1950, approximately 75% and 100% of the observed global warming is due to human influences, respectively.

Foster and Rahmstorf (2011)

Foster and Rahmstorf (2011; FR11) implemented a very similar statistical approach to that in Lean and Rind (2008).  The main difference is that FR11 examined five different temperature data sets, including satellites, and only looked at the data from 1979 to 2010 (the satellite temperature record begins in 1979).  They also limited their analysis to the three main natural influences on global temperatures – solar and volcanic activity, and ENSO.  What remains once those three effects are filtered out is predominantly, but not entirely due to human effects.  For our purposes, we will classify this remainder as the human contribution, since FR11 removed the three largest natural effects.

Using the temperature data from the British Hadley Centre (which was used by LR08, and is the most frequently-used temperature data set in these studies), FR11 found that the three natural effects in their analysis exerted a small net cooling effect from 1979 to 2010, and therefore the leftover influence, which is predominantly due to human effects, is responsible for more than 100% of the oberved global warming over that timeframe.

One key aspect of this type of study is that it makes no assumptions about various possible solar effects on global temperatures.  Any solar effect (either direct or indirect) which is correlated to solar activity (i.e. solar irradiance, solar magnetic field [and thus galactic cosmic rays], ultraviolet [UV] radiation, etc.) is accounted for in the linear regression.  Both Lean and Rind and Foster and Rahmstorf found that solar activity has played a very small role in the observed global warming.

Gillett et al. (2012)

Similar to S10, Gillett et al. applied a statistical multiple linear regression approach to a climate model – the second generation Canadian Earth System Model (CanESM2).  They used data for human greenhouse gas and aerosol emissions, land use changes, solar activity, ozone, and volcanic aerosol emissions.  In their attribution they grouped some of the effects together into ‘natural’, ‘greenhouse gas’, and ‘other’.  The authors estimated the effects of each over three timeframes: 1851-2010, 1951-2000, and 1961-2010.  For their attributions over the most recent 50 years, we took the average of the latter two, and used their ‘other’ category as an estimate for the influence of human aerosol emissions (which will result in somewhat of an underestimate, since most ‘other’ effects are in the warming direction).

Gillett et al. estimated that over both timeframes, humans are responsible for greater than 100% of the observed warming.

Human-Caused Global Warming Consensus

The agreement between these studies using a variety of different methods and approaches is quite remarkable.  Every study concluded that over the most recent 100-150 year period examined, humans are responsible for at least 50% of the observed warming, and most estimates put the human contribution between 75 and 90% over that period (Figure 2).  Over the most recent 25-65 years, every study put the human contribution at a minimum of 98%, and most put it at well above 100%, because natural factors have probably had a small net cooling effect over recent decades (Figures 3 and 4).

Additionally, in every study over every timeframe examined, the two largest factors influencing global temperatures were human-caused: (1) GHGs, followed by (2) human aerosol emissions.  This is a dangerous situation because as we clean our air and reduce our SO2 emissions, their cooling effect will dissipate, revealing more of the underlying GHG-caused global warming trend.  Note that not all studies broke out the effects the same way (i.e. only examining ‘natural’ and not solar or volcanic effects individually), which is the reason some bars appear to be missing from Figures 2 to 4.

Figure 2: Percent contributions of various effects to the observed global surface warming over the past 100-150 years according to Tett et al. 2000 (T00, dark blue), Meehl et al. 2004 (M04, red), Stone et al. 2007 (S07, green), Lean and Rind 2008 (LR08, purple), Stott et al. 2010 (S10, gray), and Huber and Knutti 2011 (HR11, light blue).

Figure 3: Percent contributions of various effects to the observed global surface warming over the past 50-65 years according to Tett et al. 2000 (T00, dark blue), Meehl et al. 2004 (M04, red), Stone et al. 2007 (S07, green), Lean and Rind 2008 (LR08, purple), Huber and Knutti 2011 (HK11, light blue), and Gillett et al. 2012 (G12, orange).

Figure 4: Percent contributions of various effects to the observed global surface warming over the past 100-150 years according to Meehl et al. 2004 (M04, red), Lean and Rind 2008 (LR08, purple), and Foster and Rahmstorf 2011 (FR11, green).

There was a period of warming between 1910 and 1940 which was predominantly caused by increasing solar activity and an extended period of low volcanic activity, with some contribution by human effects.  However, since mid-century, solar activity has been flat, there has been moderate volcanic activity, and ENSO has had little net impact on global temperatures.  All the while GHGs kept increasing, and became the dominant effect on global temperature changes, as Figures 3 and 4 illustrate.

A wide variety of statistical and physical approaches all arrived at the same conclusion: that humans are the dominant cause of the global warming over the past century, and particularly over the past 50 years.  This robust scientific evidence is why there is a consensus among scientific experts that humans are the dominant cause of global warming.

– Dana Nuccitelli, in a piece first published at Skeptical Science.

Related Post:

• It’s “Extremely Likely That at Least 74% of Observed Warming Since 1950″ Was Manmade; It’s Highly Likely All of It Was

This article was originally posted on Climate Progress

Credo Action via Flickr

by David Roberts, reposted from Grist

In October 2011, National Journal surveyed energy experts about whether Obama was likely to approve the Keystone XL pipeline, which would carry Canadian tar-sands oil through the U.S. to the Gulf of Mexico. Ninety-one percent of the “energy and environment insiders” believed he would.

On Wednesday, Obama proved them wrong.

How could the experts have gotten it so wrong? The answer is twofold: Grassroots environmentalists were stronger, and congressional Republicans dumber, than anyone predicted.

Back in August of 2011, when author and activist Bill McKibben staged the first anti-Keystone rallies around the White House, political observers scoffed. These were, after all, the same environmentalists who had been rendered irrelevant by their cap-and-trade defeat and the stress of economic recession. No way they could stop a fossil fuel infrastructure project with big money behind it.

But McKibben kept at it. The movement he seeded grew, forging strategic partnerships with Nebraska farmers, social-justice groups, and unions. Activists staged more rallies, hounded the president everywhere he went and uncovered serious questions about the relationship between the tar-sands industry and the State Department. As the crowds grew, big-money Democratic donors started weighing in on the issue. In November, under intense pressure, Obama announced that the final determination would be delayed until after the election. It was an unexpected display of muscle from the green grass roots.

Still, most observers assumed that Obama was just buying time (and the support of his environmental base) and would approve the pipeline in the spring. That’s where the dumb Republicans came in.

The GOP thought it had Obama in a trap — approve the pipeline and anger environmentalists, deny it and anger construction unions — and that the president had seemingly slipped out of that trap by delaying the decision. Infuriated, Republicans threatened to attach a rider to December’s payroll tax bill forcing Obama to make a decision within six months.

At that point, the administration made it clear that if Congress rushed it into a decision without adequate environmental review, it would reject the pipeline. Nonetheless, the GOP attached the rider to the bill. So yesterday, true to his word, Obama rejected the pipeline.

In other words, Republicans killed their own pet project. Maybe they thought they could bully Obama into submission, in which case they disastrously miscalculated. Or maybe they cared more about an election-year talking point than the pipeline itself. Either way, rank-and-file Republicans who genuinely wanted to see the pipeline built have every reason to be angry with their congressional leadership, which has again opted for tantrums over tangible policy victories.

The pipeline has not been killed for good, of course. Obama made it clear yesterday that he still believes in oil and gas development. TransCanada, the company behind the project, will reapply for a permit next year, so the battle may repeat itself then.

But for now, the fight is about who controls the message heading into November. On this, the experts are similarly unanimous: The GOP has the administration right where it wants it, stuck with yet another maddening choice of “jobs versus environment,” a dichotomy it’s happy to bring up through November.

But the experts have been wrong before (just a few paragraphs ago, in fact). The Keystone XL victory (along with the stunning reversal of momentum behind the Stop Online Piracy Act) shows that organizing still matters. Organizing brings money and intensity, which are the coin of the realm in politics. If the Keystone coalition is capable of a victory on policy, there’s no reason continued organizing can’t win a victory on messaging.

For the coalition winning that victory will mean going directly after its enemy’s purported strength: jobs. In a press conference denouncing Obama’s decision yesterday, Speaker of the House John Boehner claimed that canceling the pipeline would destroy tens of thousands of jobs. But the only independent study done on the matter, from the Cornell Global Labor Institute, found that the pipeline would create between 500 and 1,400 jobs, almost all temporary construction jobs. The State Department, meanwhile, estimates it would create 5,000 to 6,000 jobs.

By way of contrast, just a few months ago the GOP rallied to vote down the president’s American Jobs Act, which, according to a Moody’s Analytics estimate, would have created 1.9 million jobs. That a short-term pipeline project has become the heart of the GOP jobs program is a kind of reductio ad absurdum of the conservative economic agenda.

The pipeline also wouldn’t have served the (somewhat illusory) goal of “energy independence.” Americans will have no special claim on the oil piped through it. As recent reports have shown, the vast bulk of that oil will be exported to petro-hungry areas like Europe and Latin America. TransCanada officials have admitted in congressional testimony that opening Canada’s oil to export will boost its value and thus increase its price for Americans. More likely, any change in the price of oil or gasoline will be a faint signal lost amid natural fluctuations.

There are, of course, ways to create American jobs and strengthen American energy security. Most of them are under attack by the very same Republicans lamenting the loss of Keystone XL. For instance, the GOP has vowed to block extension of the Production Tax Credit that supports wind power developers. According to a study commissioned by the American Wind Energy Association (AWEA), that could lead to the loss of 37,000 jobs — good, permanent jobs. The Department of Energy’s loan guarantee program for renewables has, according to DOE, created 60,000 direct jobs in the wind and solar industries. The GOP is trying to kill it too. (Both AWEA and DOE have reason to trumpet their economic benefits, of course, but their numbers are generally taken seriously by investors.)

Supporters of clean energy can win the messaging battle if they can focus the conversation on what kind of jobs Americans want, which is to say, what kind of country Americans want. Do we want ephemeral jobs building oil infrastructure that overwhelmingly benefits those who happen to be sitting on top of the oil? Or do we want high-skill jobs in manufacturing, engineering, design, and a dozen other trades, in industries that will dominate the 21st century, with profits that stay in U.S. communities? Do we want to continue cooking the planet, or do we want to lead the way toward solutions?

Winning that messaging battle won’t be about cleverness — it will be about volume and repetition. Greens can never match the money behind fossil fuels, but as the Keystone XL fight has shown, they can out-organize and outmaneuver their opponents when they put their bodies and sweat into it. As long as they ignore the “experts,” they’ll be fine.

This article was originally posted on Climate Progress

If we want wind to continue growing, more turbines will need to be placed in our communities and close to our backyards. And that will inevitably cause more social friction.

Wind supporters cannot discount concerns from local residents about noise and visual impact. With proper communication between developers and communities, many of the potential conflicts can be mitigated or avoided.

But there’s a huge difference between concerns of neighbors to wind projects and the faux medical conditions pushed by advocates who claim turbines are a serious threat to human health.

Although no conclusive research has shown that wind farms cause health problems, many anti-wind groups have pushed the idea that “Wind Turbine Syndrome” is a widespread problem – elevating legitimate siting concerns to scare tactics.

A new study released this week by the Massachusetts Department of Environmental Protection finds that “there is no evidence for a set of health effects…that could be characterized as ‘Wind Turbine Syndrome.’” The supposed health impacts pushed by wind opponents include mental health problems, heart disease and vertigo.

The Department’s Panel was comprised of independent experts in a range of fields associated with the possible health impact of exposure to wind turbines. They explored scientific literature, reports, popular media and public comments and concluded that there was no scientific basis for claims about Wind Turbine Syndrome:

Chart courtesy of Plymouth Daily News

While the panel recommended more research on the impact of “very loud turbines” that could disrupt sleep patterns of some individuals (even though they write that a “‘very quiet wind turbine’ would not likely disrupt even ‘the lightest of sleepers’ at that same distance”), the researchers debunk the broad-based claims about Wind Turbine Syndrome:

There is insufficient evidence that the noise from wind turbines is directly… causing health problems or disease.  Claims that infrasound from wind turbines directly impacts the vestibular system have not been demonstrated scientifically. Available evidence shows that the infrasound levels near wind turbines cannot impact the vestibular system.

The study failed to produce any concrete evidence that “flicker” caused by the shadows of rotating blades causes epileptic seizure, or that turbines cause “pain and stiffness, diabetes, high blood pressure, tinnitus, hearing impairment, cardiovascular disease, [or] headache/migraine.”

In fact, the most dangerous problem in Massachusetts was from falling ice, which is “physically harmful, and measures should be taken to ensure that the public is not likely to encounter such ice.”

Zachary Rybarczyk is an intern on the energy team at the Center for American Progress. Stephen Lacey is a writer with Climate Progress.

This article was originally posted on Climate Progress

by RL Miller, cross posted from Daily Kos

This article was originally posted on Climate Progress

Almost 3000 non-science major undergraduates at the University of Chicago have taken PHSC13400, Global Warming: Understanding the Forecast, since Ray Pierrehumbert and I (David Archer) first developed it back in 1995. Since the publication of the textbook for the class in 2005 (and a much-cleaned-up 2nd edition now shipping), enrollment has gone through the roof, it’s all I’ve been able to teach the last few years, trying to keep up with demand. I hear it is the largest class on campus, with 4-500 students a year out of an annual class of only around 1400. Now the content of this class is being served to the internet world at large: Open Climate 101.

You can watch video lectures followed by quizzes to challenge and hopefully stimulate your understanding, and work your way through tutorials with interactive models and simple mathematical ideas. Actually all that stuff has been available for a long time, online or in the textbook, but now it’s packaged into an interactive assessing system, which admittedly lacks the personality and finesse of our graduate student teaching assistants, but I hope it’ll get the job done. You can work at your own pace, on your own time. You don’t get University of Chicago credit, but it’s free, and if you get to the end of it you can download a certificate of accomplishment with your name and a verification code, signed by me. I hope people find it useful.

This article was originally posted on Real Climate

Percent of Americans Who Believe the Effects of Global Warming Have Already Begun to Happen, by Political Ideology, from McRight and Dunlap

Conservative columnist Michael Gerson broke sharply from right-wing orthodoxy today when he ended an op-ed on climate change with this bombshell:

The extraction and burning of dead plant matter is not a moral good — or the proper cause for a culture war.

As evidenced by the presidential debates and recent Congressional hearings and speeches, it is in fact an article of faith for much of the national GOP that extracting and burning fossil fuels is a moral good, a matter of national security and economic security.  Drill, Baby, Drill!

Imagine Gerson telling the attendees of the Republican National Convention that what they are chanting for isn’t a moral good.  He’d be drummed out of the movement.

And in his op-ed, “Climate and the culture war,” Gerson gets that the planet is warming rapidly, creating many dangerous impacts, and the best explanation is human emissions of greenhouse gases.

Unfortunately, accompanying this bombshell is a dud, Gerson’s tired — and erroneous — blame-the-messenger strategy for the culture war:

No cause has been more effectively sabotaged by its political advocates. Climate scientists, in my experience, are generally careful, well-intentioned and confused to be at the center of a global controversy. Investigations of hacked e-mails have revealed evidence of frustration — and perhaps of fudging but not of fraud. It is their political defenders who often discredit their work through hyperbole and arrogance. As environmental writer Michael Shellenberger points out, “The rise in the number of Americans telling pollsters that news of global warming was being exaggerated began virtually concurrently with the release of Al Gore’s movie, ‘An Inconvenient Truth.’”

Obviously, any “fact” offered up by confusionist Michael Shellenberger of the Breakthrough Institute is likely to be a nonsensical myth — and this one most certainly is.  There is no polling data to support that view, as is clear from the chart above from the 2011 journal article, “The polarization of climate change and the polarization and the American publics view of global warming.”  I confirmed this with co-author Riley Dunlap when the study came out, which I’ll discuss further in a later post.

And yes, it is laughable that Gerson has the nerve to blame Gore or anybody else for the culture war or the polarization of any issue.  Gerson “served as President George W. Bush’s chief speechwriter from 2001 until June 2006, as a senior policy advisor from 2000 through June 2006, and was a member of the White House Iraq Group.”  Gore just made a movie and then use the proceeds to try to depolarize the issue whereas Bush/Cheney politicized science, and specifically climate science,  more than any administration in history.

As an aside, blaming the messenger is certainly an emerging climate strategy for many in the conservative movement since it lets them off the hook.  You see, folks, it isn’t the  disinformation campaign — which Gerson never mentions — or the power of the fossil fuel lobby — which Gerson never mentions.  It’s those darn “defenders” of scientists who are to blame.  I wonder who scientists could possibly need defending from?  But I digress.

Let me go back to the polling data because it is certainly a widely held myth that Gore is responsible for polarizing this debate.  That is a myth conservatives love to tout, of course, and it is one the breakthrough bunch has repeated again and again.  But it just isn’t true.

As an important aside, it is pretty well-known from social science research that people take crucial cues (as to their beliefs) from elites and that Republicans tend to take their cues from Republican elites and Democrats tend to take their cue from Democratic elites.  So it would be hard for Gore by himself to polarize the debate in any case.  Indeed, Gerson himself notes that:

In 2005, then-Gov. Mitt Romney joined a regional agreement to limit carbon emissions. In 2007, Gingrich publicly endorsed a cap-and-trade system for carbon.

Many, many Republicans embraced cap-and-trade around that time and didn’t flip flop on climate until 2009, suggesting again it was something other than Gore’s advocacy to blaim (see Tim Pawlenty: “Every one of us” running for president has flip-flopped on climate change).  Let’s remember that the GOP presidential nominee ran on a platform of climate action and cap-and-trade — even his conservative VP, Sarah Palin, endorsed it.  That’s a key reason again that you see in the top chart that the liberal-conservative polarization did not accelerate until 2009, when a certain person got elected with overwhelming majorities and the prospect of an actual climate bill became quite real.

And for those sticklers who point out that Gerson was referring to a different polling question, here’s Gallup’s polling on the exaggeration question:

Note that for most of the period through 2009 (other than the election year of 2004) an overwhelming majority of people believe that either the news gets it right or underestimates the seriousness of global warming.  Go figure!

Note also that this poll has a margin of sampling error of +/- 3%.  So we see it is false to claim, “The rise in the number of Americans telling pollsters that news of global warming was being exaggerated began virtually concurrently with the release of Al Gore’s movie, ‘An Inconvenient Truth’ ” — which was released in May 2006!  Indeed what’s remarkable is how little these numbers change at all within the margin of error from 1998 through 2008 (other than the election year of 2004).

And Gallup breaks these down by party ID:

Now this is a little interesting in that you see that the view of independents and Democrats hardly budged through 2008 on this question.  Even for Republicans, their 2007 and 2008 percentages were below that of 2004, and once you throw in the margin of error, any claim that Gore’s movie polarized this issue because untenable.

Aside:  There is another complicating factor for interpreting this polling.  From 2006 to 2010, “there has been an actual decrease in the number of straight Republican identifiers among registered voters (down 2 points) which has produced a concomitant increase in the number of Republican-leaning independents over the 2006-2010 time period,” as polling expert Ruy Teixera explained in November 2010.  What that means is that Republicans became more conservative (as they shed more independent-leaning R’s) and independents also  became more conservative (as they added  former Republicans).  So that accounts for some of the rise in the percentages in 2008 and 2009 for Republicans and independents.  I confirmed the plausibility of this view with Teixera last year.  That’s one reason I prefer to look at the conservative-liberal split (the top chart) than the  Democrat-Republican split.

And also note that this is one of those somewhat flawed questions that ask people to think about what is said in the news — rather than simply asking people whether they think the seriousness of global warming has been exaggerated (see “Experts Debunk Polls that Claim Sharp Drop in Number of Americans Who Believe in Global Warming“).  If we look at the polling of Stanford’s Jon Krosnick, it’s just hard to see any major trend concerning public belief about global warming that Al Gore can be blamed for:

National survey of American public opinion on global warming via Jon Krosnick, Stanford University

What makes the charge against Gore so pernicious is that the former vice president worked hard to keep the issue bipartisan after his movie came out, something that the social science community acknowledges.  You may recall the error-riddled, self-contradictory, and demonstrable false report, Climate Shift that Prof. Matthew Nisbet of American University wrote last year.  Nisbet, funded by the same folks who fund the breakthrough bunch, tried to push the exact same attack on Gore — but two of his original expert reviewers would have none of it:

• Nisbet in Exec Sum:  “Gore has consistently sought to mobilize progressives politically, pairing his messages about climate science with attacks on Republicans.”
• Max Boykoff:  “I don’t agree with that statement.”
• Robert Brulle:   “His claim about the role of Vice President Gore has no valid empirical data behind it.”

This was a classic counterfactual.  Gore reached out to Republicans in his famous WE campaign — I’m sure everyone now remembers Gingrich and Pelosi on the couch.  And there was also Al Sharpton and Pat Robertson.

“The discussion of Al Gore ignores basic scholarship on the climate denial efforts, and supports an ideological position that is not grounded in an empirical analysis,” as Robert Brulle,  a leading expert on climate communications, put it to me.

The bottom line is that there just is no polling data or social science scholarship to support the charge that Al Gore’s movie began the polarization of the climate debate —  and there is much polling data and scholarship to the contrary.

The true acceleration of the polarization occurred around 2009 — and primarily involved a shift by Republicans and Republican-leaning independents, most likely responding to elite cues by politicians and of course  the right wing media that they tend to read online, watch on TV, and listen to on the radio.

I’ll end where Gerson began:

The attempt by Newt Gingrich to cover his tracks on climate change has been one of the shabbier little episodes of the 2012 presidential campaign. His forthcoming sequel to “A Contract with the Earth” was to feature a chapter by Katharine Hayhoe, a young professor of atmospheric sciences at Texas Tech University. Hayhoe is a scientist, an evangelical Christian and a moderate voice warning of climate disruption.

Then conservative media got wind. Rush Limbaugh dismissed Hayhoe as a “climate babe.” An Iowa voter pressed Gingrich on the topic. “That’s not going to be in the book,” he responded. “We told them to kill it.” Hayhoe learned this news just as she was passing under the bus.

So the right-wing media leaped on Gingrich, who once embraced climate action and cap-and-trade, because he was going to include a chapter by a scientist who is an evangelical Christian and a moderate voice on this issue.   It really isn’t that hard to figure out who is responsible for polarizing this issue.

This article was originally posted on Climate Progress