Written by: Matt Seyer
Anthropogenic Climate Change
Today, among serious people, any discussion of climate change is conducted in the context of a broadly-held assumption: that humans are causing the climate to change (this is known as anthropogenic climate change, or ACC) and that these changes are significant and harmful. This assumption derives from overwhelming scientific support. ACC is recognized as a global problem that requires a global effort to counteract its current effects and stall its future impact. Most if not all talk of climate change involves coming up with innovative and lasting solutions to this problem. In the upcoming elections, the appropriate solutions will surely be a topic of intense debate.
Yet, one still encounters the occasional politician who seeks to instill doubt in the public as to the veracity of the assumption that ACC is occurring. This is harmful, generally speaking, in the same way that it would be harmful if one of our leaders questioned whether or not nicotine was addictive. An assertion so empirically false slows our progress in combating the issue. It creates unnecessary confusion and ultimately wastes time; never mind how irresponsible it is. Among the general public, such skepticism could be warranted, given that some might not have access to or be aware of the latest scientific research on the topic. But among our leaders, who absolutely do have said access, this is completely inexcusable.
While I would never call Texas Gov. Rick Perry my leader, for better or worse he is a leader, and as a presidential contender he has a very loud microphone through which to voice his opinions. He has made it clear he does not believe that human beings are contributing to climate change, and he expounded on the issue in detail at a campaign stop in Bedford, N.H.
“I do believe that the issue of global warming has been politicized. I think there are a substantial number of scientists who have manipulated data so that they will have dollars rolling into their projects. I think we’re seeing it almost weekly or even daily, scientists who are coming forward and questioning the original idea that man-made global warming is what is causing the climate to change.”
He added that plans to address climate change by limiting carbon emissions would cost “billions, if not trillions” and that America should not spend that much money on “scientific theory that has not been proven and from my perspective is more and more being put into question.”
Perry is not alone by any means. Here’s another Republican leader and presidential candidate, Tim Pawlenty:
“The weight of the evidence is that most of it, maybe all of it, is because of natural causes…There’s lots of layers to it. But at least as to any potential man-made contribution to it, it’s fair to say the science is in dispute.”
Are they correct? Is there substantial disagreement on the causes of climate change? There absolutely is not.
Let’s take it from the top, starting with synthesis reports. Synthesis reports are assessments of scientific literature that compile the results of a range of stand-alone studies in order to achieve a broad level of understanding, or to describe the state of knowledge of a given subject.
One synthesis report that is widely referenced is from the U.N. Intergovernmental Panel on Climate Change (IPCC), a scientific body considered the leading international organization on climate science. It details the scientific consensus of thousands of researchers from 194 countries. The most recent report states:
“Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic [human-caused] greenhouse gas concentrations…The observed widespread warming of the atmosphere and ocean, together with ice mass loss, support the conclusion that it is extremely unlikely that global climate change of the past 50 years can be explained without external forcing, and very likely that it is not due to known natural causes alone.” (External forcing refers to anything outside of the normal climate system that changes the climate, including the results of human activity, sunspots or volcanic eruptions.)
In the United States, the U.S. Global Change Research Program coordinates and integrates federal research on climate. Its 2009 report mirrored the IPCC’s conclusions:
“Observations show that warming of the climate is unequivocal. The global warming observed over the past 50 years is due primarily to human-induced emissions of heat-trapping gases. These emissions come mainly from the burning of fossil fuels (coal, oil, and gas), with important contributions from the clearing of forests, agricultural practices, and other activities.”
Again in the United States, a committee was organized by the National Academy of Sciences and the National Research Council. This committee was tasked with reviewing the current research on climate change. The committee’s conclusions were straightforward and clear: climate change is occurring, it is caused primarily by the emission of greenhouse gases from human activities, and it poses significant risks for a range of human and natural systems. In fact, it made a point of rejecting the view that those findings are in some way questionable:
“Although the scientific process is always open to new ideas and results, the fundamental causes and consequences of climate change have been established by many years of scientific research, are supported by many different lines of evidence, and have stood firm in the face of careful examination, repeated testing, and the rigorous evaluation of alternative theories and explanations.”
While we’re on the topic of the National Academy of Sciences, it should be noted that the National Academies of 32 other countries, including Brazil, Japan, Germany, Canada, France, China, India, Russia, the UK, and Italy have all issued similar statements.
Several science organizations within the United States affirm the authenticity of ACC, including the American Association for the Advancement of Science, the American Chemical Society, the American Institute of Physics, the American Physical Society, the American Geophysical Union, and the Geological Society of America, among many others.
This might all be good and well, but are we not running the risk of tunnel vision? Are we really considering the broader spectrum of scientists? Several scientific studies have attempted to quantify just how much agreement there is among scientists when it comes to climate change.
A 2010 study published in the Proceedings of the National Academy of Sciences found that out of 1,372 climate researchers under review, approximately 97 to 98 percent of those actively publishing in the field said they believe human beings are causing climate change. An earlier survey published in the 2009 issue of Eos – a publication of the American Geophysical Union – asked scientists (approximately 3,146) from a wide range of disciplines: “Do you think human activity is a significant contributing factor in changing mean global temperatures?” Approximately 82 percent of the surveyed scientists answered yes to this question. Of those climate change specialists surveyed, 97.4 percent answered yes.
When it comes to anthropogenic climate change, there is a clear, widespread consensus among multiple scientific bodies from multiple industrialized nations. Within the United States, several major science organizations, including our own National Academy, independently affirm the consensus, along with 97% of climate researchers actively publishing in the field. This is more than enough to assume ACC as a scientific fact and to move on from there.
What of Perry’s second charge: that a substantial number of scientists have fudged their data? Perry never goes into specifics, but it’s a safe bet that he’s referring to Climategate, an incident so fraught with misrepresentation and absurdity that it would take me many more pages just to detail the basics. In short, Climategate was a carefully constructed and skillfully executed hoax. (http://blogs.discovermagazine.com/badastronomy/2011/08/24/case-closed-climategate-was-manufactured/) Again, our leaders cannot responsibly allude to such an incident as though it were cause for doubt.
Perry, Pawlenty, and other Republican leaders would have us believe that the science of climate change and its human causes is in dispute. They tell us that skepticism is growing, that scientists are manipulating data. They couldn’t be more wrong. Anthropogenic climate change is a serious issue, one that will require humanity to work in unison in order to avoid the consequences. We count on our leaders, who have access to all of the proper information, to be the first to embrace the reality of such issues and thus the first to begin working on the solutions. It’s time to get serious, and, especially in the 21st century, it’s time to stop disavowing sound science.