Science Policy For All

Because science policy affects everyone.

Perspective on Climate Change: Supporters versus Skeptics

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By: Nivedita Sengupta, PhD

        A recent United Nations report shows that earth’s surface temperature is rapidly hurtling towards a two degrees Celsius increase. Scientists say that the world must stay below two degrees to avoid the worst effects of climate change. However solving this issue can be challenging and overwhelming. The science used to generate the evidence for climate change is complicated and the predictions carry many caveats and asterisks. Nonetheless the major question that stands out is, “What is climate change and why people are skeptic about it?”

The definition of climate change itself triggers a difference in opinion. According to the Intergovernmental Panel on Climate Change (IPCC), climate change refers to “A change in the climate that persists for decades or longer, arising from either natural causes or human activity”. This definition differs from that in the United Nations Framework Convention on Climate Change (UNFCCC), where climate change preferentially refers to “A change of climate that is attributed directly or indirectly to human activity that alters the composition of the global atmosphere.” Instead, UNFCCC defines a change in climate over comparable time periods because of natural causes as climate variability.

Keeping these definitions aside, many policymakers and major corporations worldwide have agreed and expressed willingness to address climate change. They believe the scientific evidence generated so far demands action. But some scientists, economists, industry groups, and policy experts continue to insist that there is no need for policy changes. Ironically many people concede with them and insist that the entire problem is exaggerated. The debate between the supporters and the skeptics is ingrained, and both groups deride each other with countless claims and counterclaims on both the science and proposed policy solutions.

Surprisingly, some climate-change skeptics do admit that the earth is warming. But they debate the cause, its potential impact, and whether human intervention is affecting it. As Myron Ebell, the president elects’ select candidate for leading the transition of the Environmental Protection Agency, stated his views on climate change “I agree that carbon dioxide is a greenhouse gas, and its concentrations in the atmosphere are increasing as a result of human activities—primarily burning coal, oil, and natural gas, where I disagree is whether this amounts to a crisis that requires drastic action.”

So what are the premises on which the skeptics insist that the current policies addressing the issue of climate change are unwarranted and dispensable? Broadly, this question can be answered by discussing the views of skeptics versus supporters on three major points of concern.

First, what is global warming and is it really happening?


The skeptics argue that the earth is not warming. They contend that the satellite-based temperature measurements, taken across the earth’s surface, indicate no measurable change in the last 30 years, and that the measuring standards are different in every place resulting in inconsistent readings. Besides, the IPCC’s graph of “global” temperatures is incorrect as they do not state the earlier cool period of about 1400 or a very warm period from about 900 to 1050 when the temperatures in Europe were several degrees warmer than today. They also make the point that warming is natural and if the earth was warmer during those periods and consecutively cooled down via some natural mechanisms, then that will happen in the future too.


According to IPCC and National Aeronautics and Space Administration (NASA), records of temperature that date back to the distant past, generated by analysis of ice cores and sediments, are quite accurate and suggest that the warming in recent decades is way higher than any period over the past millennium. Gavin Schmidt, director of NASA’s Goddard Institute for Space Studies, said, “It’s unprecedented in 1,000 years.” 15 out of the 16 hottest years in NASA’s 134-year record have occurred since 2000.

Second, is there any real impact because of climate change?


Skeptics believe that climate change has no impact whatsoever and is not responsible for the extreme weather catastrophes in recent times. It has happened in the past and has no connection with either global warming or increased levels of carbon dioxide.


The supporters says that the impacts are everywhere starting from the melting of polar ice sheets to endangered biodiversity, which will eventually risk human health and society. In the US alone, numerous weather and climate-born billion-dollar disasters have occurred from 1980-2016, the most recent being the historic flood devastating a large area of southern Louisiana.

Third, and the most disputed subject is…

Are human beings really responsible for climate change?


According to skeptics the carbon dioxide levels are not high enough to elicit concern as the current carbon dioxide levels were exceeded in the last 150 years. Besides, they argue that water vapor, and not carbon dioxide, is the significant greenhouse gas because it absorbs more radiant heat than carbon dioxide and makes up about 3% of the atmosphere compared to 0.03% by carbon dioxide. The current level of carbon dioxide contributes to about 3% of the total warming and hence the anthropogenic carbon dioxide contribution to total warming is, at the most, about 0.1%. Therefore carbon dioxide generated because of “human interference” has no discernible role in global warming. They consider carbon dioxide as beneficial for the environment and attribute other factors like aircraft exhaust, cosmic rays, solar winds, magnetic fields and solar intensity as causes of climate change. They state that no definitive factor for climate change has been established yet and any assertive statements about current and future climates should be regarded with skepticism.


IPCC in its 2014 climate change report states, “Human influence on the climate system is clear, and recent anthropogenic emissions of greenhouse gases are the highest in history.” Global warming is primarily a problem of too much carbon dioxide in the atmosphere. This carbon overload is caused mainly when we burn fossil fuels like coal, oil and gas or cut down and burn forests. Burning of fossil fuels to make electricity is the largest source of heat-trapping pollution. Though water vapor is the most abundant heat-trapping gas, it has a short cycle in the atmosphere and cannot build up in the same way carbon dioxide does. Preventing dangerous climate change requires very deep cuts in carbon dioxide emissions, as well as the use of alternatives to fossil fuels worldwide.

In 2015, the Paris Agreement was made within the UNFCCC to deal with climate change by reducing greenhouse gases emissions starting in 2020. So far, 114 out of 197 countries have ratified with the agreement and vouched to cut down emission. On September 2016, the United States of America joined the Paris agreement along with China, another big emission producing country. President Obama called it a top concern and said “For all the challenges that we face, the growing threat of climate change could define the contours of this century more dramatically than any other challenge”. In contrast, president-elect Donald Trump has shown a skeptic view on this matter and has described climate change as “bullshit” and a “hoax. He vowed to dismantle the EPA and withdraw United States from the Paris Agreement to reduce the damage on economy created by climate change alarmists. However, there are a handful of elected members who offer some hope to fight the cause of climate change in coming years. Five candidates with strong climate credentials won offices in Congress, and they have impressive personal and political backgrounds. In the present situation it’s critical that the world stays on course with rational, prompt and comprehensive action to mitigate climate change.

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Written by sciencepolicyforall

December 8, 2016 at 9:00 am

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