The scientific agreement that climate change is happening, and that it's caused by human activity, is significant and growing, according to a new study published Thursday. The research, which is the most comprehensive analysis of climate research to date, found that 97.1% of the studies published between 1991 to 2011 that expressed a position on manmade climate change agreed that it was happening, and that it was due to human activity.
The study looked at peer reviewed research that mentioned climate change or global warming. Peer review is the way that scientific journals approve research papers that are submitted. In peer review, group of scientists that weren't involved in the study, but who are experts in the field, look at the research being submitted and have approved that it meets scientific process standards, and the standards of that journal.
In 2011, 521 of those peer reviewed papers agreed that climate change is real, and that human activity is the cause. Nine papers in 2011 disagreed.
John Cook, founder of skepticalscience.com and the lead author on the study, said the motivation for the analysis was the importance of scientific consensus in shaping public opinion, and therefore policy. "When people understand that climate scientists agree on human-caused global warming, they're more likely to support climate policy," Cook said. "But when the public are asked how many climate scientists agree that humans are causing global warming, the average answer is around 50%."
This "consensus gap" is what Cook and the research team is trying to close. "Raising awareness of the scientific consensus is a key step towards meaningful climate action," Cook said.
This study is not the first to examine the overwhelming agreement among climate scientists. Surveys of actively publishing climate scientists as well as analyses of climate change papers have shown similar results.
In 2004 Naomi Oreskes, Professor of History and Science Studies at the University of California San Diego, published what many scientists consider the seminal study on climate change consensus. She also co-authored the book Merchants of Doubt, which identifies and examines the similarities between today's climate change conversation and previous controversies over tobacco smoking, acid rain, and the hole in the ozone layer.
Oreskes believes that the public isn't aware of the consensus because of deliberate efforts to cause confusion. "There has been a systematic attempt to create the impression that scientists did not have a consensus, as part of a broader strategy to prevent federal government action," Oreskes said. "The public have been confused because people have been trying to confuse us."
The study published Thursday is the first to take so many papers and authors into account. Doing a search on the popular science article website Web of Science for "climate change" or "global warming" produces over 12,000 results. Of these, 4,014 papers were identified to state a position on climate change. Among those, 3,896, or 97.1% endorsed the consensus that climate change was happening and that it was caused by human activity.
In an interesting result, Cook and his team found that over time, scientists tend to express a position on climate change less and less in their research papers. This is likely a result of consensus -- that if a scientific conclusion has been reached, there's no need to continue to state that conclusion in new research. "Scientists tend to take the consensus for granted," says Cook, "perhaps not realizing that the public still think it's a 50:50 debate."
Magical Mystery Tour: Unicorns, Yeti and the Loch Ness Monster
I am taking a hiatus from my “What Can I Do Series.” This blog will focus on three stories in the press in the past few months that have been flaring up. They have been smoldering for years and I expect they will smolder for a few more years.
As background, more than a year ago I wrote a piece entitled Form of Argument: Adventures in Rhetoric. In that blog I named a number of items to look for in politically motivated articles on climate change. One of the most common forms of argument is to look at one item of information and to ignore other information. Once this information is put at the center of the argument, a set of yes or no questions or statements that suggest contradictory knowledge follow it. This form of argument produces doubt, amplifies uncertainty and effectively disrupts a societal or governmental response to climate change. Also in that original blog, I warned of emotional appeals that suggested dishonesty and disreputable behavior. In the following examples, these elements of argument appear (see also Changing the Media Discussion and Lemos and Rood on the Uncertainty Fallacy).
All of the items that I discuss below are items that have been addressed in this blog previously. A reason that I am writing about them this week is that recently other writers have put together excellent discussions of the scientific knowledge and the communication of that knowledge. Also I refer to the web site Skeptical Science which has an ongoing collection of arguments against climate change science and their counters.
From a scientist - citizen perspective, the Economist article is a good article and it demonstrates some of the perils of communication and science driven by public dialogue. For example, the surface global temperature plots were in the 1990s highly touted as a communication tool to provide the story to policy makers and the people. However, it is known to be too simplistic, and the models were never built as predictive models.
From a scientist perspective, the global surface temperature record is not a singular or robust measure of planetary warming. There is heat going into oceans and melting sea ice and melting ice sheets and melting permafrost. I think an interesting tension is that there is a growing literature that the Earth is heating faster than predicted, when all of these other measures of heating are considered.
Judith Curry has a recent post on the warming pause in which she summarizes David Appell’s article W[h]ither Global Warming: Has it slowed down?. In great detail the reasons why the surface temperature record is not a singular measure of planetary warming are discussed. As we search for the heat and find it, largely in the ocean, all observations suggest that the planet is warming, and that the dominant cause is human-generated greenhouse gases from burning fossil fuels.
It has been a cold spring in the U.S.: The 2013 spring has been one of the most peculiar in my life. This follows 2012, which was just stunningly hot. 2013 has had a lot of record cold in the U.S. There has also been a lot of variability, record cold followed by record warm. Marshall Shepherd brought the article Cooler Spring Weather Does Not Equal a Cooling Climate to my attention. This article makes reference to a video from Climate.gov entitled Pockets of Cold on a Warming Planet. All I have to say here is the U.S. is not the world, globally March 2013 was the tenth warmest ever and for the past 337 months the global temperature has been higher than the twentieth century average. April will be number 338. Here is one of my old links on this subject Warm Cold Warm Cold.
Carbon Dioxide Increase is Good for the Plants and not Correlated with Temperature: There was an article in the Wall Street Journal, Defending Carbon Dioxide. I note that it was an opinion piece. It was full of opining with no cohesive basis in fact and isolated misrepresentation of fragments of knowledge. It misrepresents both climate knowledge and ecological knowledge. It was released to coincide with the atmospheric carbon dioxide crossing 400 parts per million. All I have to say about this is that carbon dioxide is a waste product and I can name numerous waste products that are good for plants. We choose to manage our sewage.
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A note or two: I am glad to see in the various articles I reference here scientists becoming more circumspect about how we communicate about climate change. We see a number of places where attempts to make communication simple contributes to perpetuation of disruptive political arguments. We set up the isolated piece of information that falls prey to the yes-no questions that generate doubt.
And as for 400 parts per million of carbon dioxide – “never before experienced by humans.” That was true for 399, 398, 397 … and it will be true for 401, 402, 403 ... Silly.
From Skeptical Science which has an on going collection of arguments against climate change science and their counters.
Moderation of comments: I have been getting more and more complaints about what is going on in the comments. WU and I will be addressing this. To start, here is a modified version of Dr. Master’s Blog Contents Rules.
Rood's Rules of the Road
1. Please do not carry on personal disputes. 2. Keep it civil. Personal attacks, bickering, flaming and general trollish behavior will not be tolerated. Disagreements are fine, but keep them civil. 3. No spam. 4. Stay on the topic of climate change or the entry topic. 5. Foul language is not allowed. 6. Please avoid topics that would be considered adults only. Many children come to this site looking for information. 7. Threats and intimidation, especially that which extends into the real world will be dealt with accordingly. 8. Do not circumvent a ban. Most bans last 24 hours or less; please accept the ban. If you create a new username to circumvent a ban, you will be blocked from the site completely.
This is the continuation of a series in response to the question, “What can I do about climate change?” Links to the previous entries are listed at the end.
Last week rather than taking the conventional view of looking at greenhouse gas emissions from the burning of fossil fuels, I presented an accounting of the emissions associated with agriculture. My primary points were that agriculture was a major emitter of greenhouse gases, and, therefore, the choices we make individually and collectively about what we eat have large environmental consequences.
I want to explore more the impact of agriculture, particularly livestock. First, however, I want to remind folks of the series on calculating budgets. Last summer I did a series where I compared the basic methods of climate science to keeping a budget – just like a checking and savings accounts. One of the entries in that series looked specifically at complexity. The idea being that despite the fact that maintaining a budget is a relatively simple matter of addition and subtraction, if you consider all of the ways we get and spend money, then it can become remarkably complex.
I implied the complexity of accounting for the greenhouse gas emissions of agriculture in the previous entry. The amount of emissions from the direct use of fossil fuels is relatively small. Big sources of emissions come from removing trees and changing forests to agricultural lands and soil management. Many aspects of soil management influence how much carbon and nitrogen is stored in the soil. There is also the need to consider greenhouse gases other than carbon dioxide: for example, methane associated with ruminates and solid waste from livestock and nitrous oxide associated with fertilizer. Emissions also depend on:
- what crops are grown and what animals are raised
- agricultural practice, for example, whether the land is plowed or no-till methods are used
- policy, for example, renewable energy policy provides incentives and disincentives on what to grow
- biological processes that are different from field to field, region to region, year to year, and that are not highly quantified
The calculation of the budget of emissions from agriculture is a difficult problem. We can say with certainty the emissions are large and they change based on many factors. We can also say that the impact of agriculture on the environment is more far reaching than climate change. Anecdotally, most people think of the impacts of pesticides and herbicides, the issues of genetically modified organisms, soil erosion and water quality before they think of how agriculture and climate change play together. Agriculture is also a major focus of those who think about sustainability.
I ended the previous entry with a relatively weak statement that what we chose to eat or not eat does make a difference. I stated that at the top of the list, perhaps, the easiest decision is to eat less meat. The issue of eating meat, of course, steps into a set of the more controversial subjects of our society. For example, there are the issues of personal choice and intrusion into individual's lives. Also, there are those who place high value on the ethics of raising and slaughtering animals. There is no doubt, however, that livestock production uses immense resources.
“Livestock’s contribution to environmental problems is on a massive scale and its potential contribution to their solution is equally large. The impact is so significant that it needs to be addressed with urgency. Major reduction in impact could be achieved at reasonable cost.”
As strong as this statement is, there is a school of thought that Livestock’s Long Shadow is a significant underestimation of the emissions due to livestock. Most notably is an analysis by Robert Goodland and Jeff Anhang, Livestock and Climate Change, which does a different accounting of the budget of emissions of greenhouse gases. In Livestock and Climate Change it is maintained that there is significant undercounting and misallocation in the United Nations budget calculation. A point that is particularly important is that the proliferation of livestock production is human-made just as much as any building, road or power plant. Therefore, for example, the carbon dioxide of respiration of the animals needs to be considered in the budget calculation. Taking all of the budget changes in Livestock and Climate Change, the conclusion is that livestock is responsible for 51 percent of the total emissions. With this number, a far larger intervention is needed than “eat less meat.”
In December 2009, I took a group of students to the 15th Conference of the Parties in Copenhagen. When I got off the subway at the conference center, there were two loud groups of advocates. One was People for the Ethical Treatment of Animals, who had gone around Copenhagen and placed markers on utility poles and in trees where sea level would be if the Greenland ice sheet melted. Another group claimed that if we were all vegetarian, then we could reduce global warming by 70 percent.
The numbers in Livestock and Climate Change follow from a well-reasoned argument in the calculation of the budget of the emissions due to livestock. However, they are not without controversy. This controversy can be found in a number of places on the web: Columbia Journalism Review and Lifting Livestock's Long Shadow, Nature Climate Change and Measuring Livestock's Long Shadow, NYTimes. At the center of the controversy is another accounting of the impact of livestock, Cleaning the Air: Livestock's Contribution to Climate Change by Maurice Pitesky and others. This paper takes a vastly different accounting and concludes that impact of livestock is much smaller than in the United Nations Report, Livestock’s Long Shadow. An interesting aspect of its argument is that “The fact that land-use changes associated with livestock (i.e., forested land converted to pasture or cropland used for feed production) are a significant source of anthropogenic GHGs in Latin America and other parts of the developing world is apparent. However, it is likely that any kind of land-use change from the original forestland will lead to great increases in global warming.” The argument being that development in countries with growing population will lead to deforestation. Their argument is carried further “The United States and most other developed countries have not experienced significant land-use change practices around livestock production within the last few decades. Instead, over the last 25 years forestland has increased by approximately 25 percent in the United States and livestock production has been intensified (concentrated geographically), thus reducing its geographical footprint.”
In this food niche of strategies to mitigate climate change, we see the same arguments emerge as in the discussion of fossil fuels. We could be more efficient in our use of resources. With efficiency, however, in the face of a growing population and growing consumption, we are still faced with a growth of emissions of greenhouse gases. Therefore, if climate-change and broader environmental issues are given priority, then we must consume less of those products that are responsible for our largest greenhouse emissions. We can conceive of sources of renewable energy that are free of carbon dioxide emissions. However, it is more difficult to imagine how we raise livestock without the methane and nitrous oxide emissions, and these greenhouse gases cannot be dismissed.
My original list topper on diet was eat less meat. If we take the high emissions scenario as correct, then a climate priority calls for an intervention into our dietary practices that is comparable to the intervention required for reducing fossil fuels. This is a change in diet that I assert will be more difficult than the change in our energy system. Therefore, back to the original question, “What can I do about climate change?” – eat (a lot) less meat. Vegetarianism is good for the planet. This from a man who does eat a lot less meat than he used to, but has been, I maintain, overidentified with BBQ.
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Some dietary resources: I have not checked these out too closely!
Setting Up the Discussion Deciding to do something, definition of mitigation and adaptation, and a cost-benefit anchored framework for thinking about mitigation
The Complete List Eight categories of things we can do to reduce greenhouse gases
We Are What We Eat Counting agriculture and its emissions of greenhouse gases
Moderation of comments: I have been getting more and more complaints about what is going on in the comments. WU and I will be addressing this. To start, here is a modified version of Dr. Master’s Blog Contents Rules.
Rood's Rules of the Road
1. Please do not carry on personal disputes. 2. Keep it civil. Personal attacks, bickering, flaming and general trollish behavior will not be tolerated. Disagreements are fine, but keep them civil. 3. No spam. 4. Stay on the topic of climate change or the entry topic. 5. Foul language is not allowed. 6. Please avoid topics that would be considered adults only. Many children come to this site looking for information. 7. Threats and intimidation, especially that which extends into the real world will be dealt with accordingly. 8. Do not circumvent a ban. Most bans last 24 hours or less; please accept the ban. If you create a new username to circumvent a ban, you will be blocked from the site completely.
Two studies done in 2009 and 2010 found that 97% of actively publishing climate scientists agree that humans cause global warming. But what would a larger sample of the scientific literature show, extended all the way up to 2011? You're invited to help find out, by participating in an anonymous 10-minute survey where you will be reading the abstracts (summaries) of ten randomly selected technical papers on Earth's climate published between 1991 and 2011. The survey was created by physicist John Cook of The Global Change Institute at Australia's University of Queensland. Mr. Cook is the creator of one of my favorite climate change websites, skepticalscience.com. He authored one of our special Earth Day 2013 essays, Closing the Consensus Gap on Climate Change, from which I have pulled Figure 1 below. Mr. Cook is lead author on a new paper called "Quantifying the consensus on anthropogenic global warming in the scientific literature," to be published in the next month or so in Environmental Research Letters. The paper analyzes the same papers included in the survey you're asked to participate in, and the researchers plan to compare the results. Each of these 11,944 papers written by 29,083 authors and published in 1,980 journals included the keywords "global warming" or "global climate change" in their listing in the ISI Web of Science database. After reading each abstract, you will be asked to rate the level of endorsement within the abstract for the proposition that human activity (i.e., anthropogenic greenhouse gases) is causing global warming. There will be these choices available on a drop-down menu for you to choose from:
1. Explicit Endorsement with Quantification: abstract explicitly states that humans are causing more than half of global warming. 2. Explicit Endorsement without Quantification: abstract explicitly states humans are causing global warming or refers to anthropogenic global warming/climate change as a given fact. 3. Implicit Endorsement: abstract implies humans are causing global warming. E.g., research assumes greenhouse gases cause warming without explicitly stating humans are the cause. 4. Neutral: abstract doesn't address or mention issue of what's causing global warming. 5. Implicit Rejection: abstract implies humans have had a minimal impact on global warming without saying so explicitly. E.g., proposing a natural mechanism is the main cause of global warming. 6. Explicit Rejection without Quantification: abstract explicitly minimizes or rejects that humans are causing global warming. 7. Explicit Rejection with Quantification: abstract explicitly states that humans are causing less than half of global warming. 8. Don't know.
When you are all done, the survey will let you know how your average score for the ten papers compares to the rating given by the authors. The survey took me about 8 minutes to complete, and it was interesting to see the tremendous diversity of research being done on global warming in my random sample. I'll post about Mr. Cook's results when his paper is published in the next few months.
Figure 1. Two recent studies have sought to measure the level of agreement in the scientific community in different ways and arrived at strikingly consistent results. A 2009 study led by Peter Doran surveyed over 3,000 Earth scientists and found that as the scientists' expertise in climate change grew, so did the level of agreement about human-caused global warming. For the most qualified experts, climate scientists actively publishing peer-reviewed research, there was 97% agreement. Alternatively, a 2010 analysis led by William Anderegg compiled a database of scientists from public declarations on climate change, both supporting and rejecting the consensus. Among scientists who had published peer-reviewed climate research, there was 97% agreement. However, it is worth pointing out that science is not decided by majority vote. This is articulated concisely by John Reisman who says: "Science is not a democracy. It is a dictatorship. It is evidence that does the dictating." Figure and text taken from Mr. John Cook's special Earth Day essay, Closing the Consensus Gap on Climate Change.
The remarkable storm that brought record-breaking May snows and cold to the Midwest last week continues to spin over the Southeast U.S. The storm is unleashing flooding rains, bringing a case of "Weather Whiplash" to Georgia: flooding where extreme drought had existed just a few months ago. The storm formed when a loop in the jet stream of extreme amplitude got cut off from the main flow of the jet over the weekend, forming a "cutoff low" that is now slowly spinning down as it drifts east over the Southeast U.S. On Sunday, the storm dumped 3.4" of rain on Atlanta, Georgia--that city's sixth heaviest May calendar day rain storm since record keeping began in 1878. Remarkably, the rains were also able to bring rivers in Central Georgia above flood stage. This portion of the country was in "exceptional drought"--the worst category of drought--at the beginning of 2013.
Figure 1. The record May snowstorm that hit the Midwest U.S. on May 1 - 3, 2013, got cut off from the jet stream and was seen spinning over the Southeast U.S. on Sunday, May 5, in this image from NASA's MODIS instrument. The 3.4" of rain that fell on Atlanta, Georgia on May 5 was that city's sixth heaviest May calendar day rainfall since record keeping began in 1878.
Weather Whiplash Weather Whiplash--a term originally coined by science writer Andrew Freedman of climatecentral.org to describe extreme shifts between cold and hot weather--is also a excellent phrase we can use to describe some of the rapid transitions between extreme drought and floods seen in recent years. I brought up a remarkable example in mid-April, when a 200-mile stretch of the Mississippi River north of St. Louis reached damaging major flood levels less than four months after near-record low water levels restricted barge traffic, forcing the Army Corp to blast out rocks from the river bottom to enable navigation. As the climate warms, the new normal in coming decades is going to be more and more extreme "Weather Whiplash" drought-flood cycles like we have seen in the Midwest and in Georgia this year. A warmer atmosphere is capable of bringing heavier downpours, since warmer air can hold more water vapor. But you still need a low pressure system to come along and wring that moisture out of the air to get rain. When natural fluctuations in jet stream patterns take storms away from a region, creating a drought, the extra water vapor in the air won't do you any good. There will be no mechanism to lift the moisture, condense it, and generate drought-busting rains. The drought that ensues will be more intense, since temperatures will be hotter and the soil will dry out more.
Figure 2. Weather Whiplash in Georgia, 2013: the center of the state was in exceptional drought as the beginning of the year, but heavy rains in February, March, and April busted the drought. Heavy May rains have now brought flooding. Image credit: U.S. Drought Monitor.
Weather Whiplash in the Southeast U.S. more likely due to an intensification of the Bermuda High This year's "Weather Whiplash" in Georgia is the second time in the past decade the state has gone from exceptional drought to flood. In September 2007, Atlanta, Georgia was in the midst of a 1-in-100 year drought, and was just weeks away from running out of water. Yet just two years later, the drought had been busted, and a phenomenal 1-in-500 year flood ripped through the city, killing ten and causing $500 million in damage. According to a 2011 study by a Duke University-led team of climate scientists, "Changes to the North Atlantic Subtropical High and Its Role in the Intensification of Summer Rainfall Variability in the Southeastern United States", the frequency of abnormally wet or dry summer weather in the southeastern United States has more than doubled in recent decades, due to an intensification of the Bermuda High. The scientists found that the Bermuda High, which is centered several hundred miles to the east of the Southeast U.S., has grown more intense during summer and has expanded westwards over the past 30 years. Since high pressure systems are areas of sinking air that discourage precipitation, this has made abnormally dry summers more common over the Southeast U.S. However, in summers when the Bermuda High happens to shift to the east, so that high pressure is not over the Southeast U.S., the stronger winds blowing clockwise around the Bermuda High bring an increased flow of very moist subtropical air from the south to the Southeast U.S., increasing the incidence of abnormally wet summers. Thus, the intensification of the Bermuda High has made extreme droughts and extreme floods more likely over the Southeast U.S. Using climate models, the scientists determined that human-caused global warming was likely the main cause of the significant intensification in the Bermuda High. Thus "Weather Whiplash" between drought and flood will probably become increasingly common in the coming decades over the Southeast U.S.
Figure 3. Observed June-July-August departure of precipitation from average over the SE United States for a 60-yr period (mm day−1). Horizontal dashed lines represent 1 standard deviation of the summer rainfall. Note that summer precipitation extremes exceeding one standard deviation have more than doubled during the most recent 30-year period compared to the previous 30-year period. Image credit: Li et al., 2011, Journal of Climate.
New climate change blog at The Guardian In these days of steadily decreasing media coverage of climate change (and all science, in general), its good to see a fresh new source of good science appear in a major newspaper. The Guardian, a prominent UK news source, has a new blog called Climate Consensus – The 97%. The primary authors are Dana Nuccitelli of SkepticalScience and John Abraham, Associate Professor at the University of St. Thomas in Minnesota. The first post at the new blog is titled “Why is Reuters puzzled by global warming’s acceleration?”
Related Links Don't miss the summary post on last week's remarkable snow storm by wunderground's weather historian, Christopher C. Burt, The Phenomenal May Snowstorm of May 1-3, 2013
These blogs are a compilation of Dr. Jeff Masters, Dr. Ricky Rood, and Angela Fritz on the topic of climate change, including science, events, politics and policy, and opinion.
