Is global warming natural or man made ?

Mutum Inaobi Singh
 Global Warming is a topic of debate among the scientific community  worldwide since long time. It is perhaps the most talked about topic of this century until COVID-19 emerged recently. There are two groups of scientists who argue for and against the human-caused global warming theory as the dominant factor for the present climate change. One group of scientists represented by United Nations’ Intergovernmental Panel on Climate Change(IPCC) support the theory while the other group represented by scientists so called climate skeptics reject the theory. The debate got momentum after the signing of the first international climate agreement in Kyoto, Japan in 1997 and it was further escalated by  democrat Al Gore, former Vice President of USA in 2006-2007 as he started the publicity campaign on global warming and climate change in the form of a documentary film called “An Inconvenient Truth”. During his campaign, he claimed that the present climate change is due to excessive release of CO2 by human over the last 200 – 250 years (since Industrial revolution in the eighteenth century). He also claimed that the controversy on the climate science is settled and all the scientists except few skeptics have consensually agreed the human-caused global warming theory of the IPCC. However, Al Gore’s claim was strongly opposed by many scientists worldwide and to show their strength against the IPCC theory, they intensified the protest campaign that started in 1998.  The main purpose of the protest campaign was to counter the claim of “settled science” and  “scientific consensus” in favour of the hypothesis of human-caused global warming as the main factor for the climate change today. Surprisingly, 31,487 scientists including 9,029 PhDs signed the Petition till March, 2008. Interestingly, the protest Petition was also supported and endorsed by the famous scientist Frederick Seitz, past president, of National Academy of Sciences, U.S.A. Besides, the IPCC’s view of climate science was also openly dissented by over 400 prominent scientists from more than 24 countries (US Senate Report 2007). The followings are some of the points put forward by the scientific community who oppose the IPCC’s theory of human induced global warming as the dominant factor for the present climate change.
According to the scientists who oppose the IPCC theory, there is no such thing called “settled science” and  “scientific consensus” on the issue of global warming and climate change as claimed by IPCC. These scientists instead claimed that the human caused global warming hypothesis does not have convincing scientific evidence and that government action on the basis of this hypothesis would unnecessarily damage both human prosperity and the natural environment of the Earth. To them, the present climate change is natural and it is not man made as claimed by IPCC. The 0.85 degree  centigrade increase in the average global temperature over the last 100 years is entirely consistent with well established long term natural climate trends which varied within a range of 3 degree centigrade. They also claim that there is substantial scientific evidence that proves, increase in atmospheric carbon dioxide produce  many beneficial effects upon the natural plant and animal environment of the Earth.  There is no scientific proof to define the current global warming is caused by anthropogenic greenhouse gases emission. According to these scientists, the human-caused global warming hypothesis is without scientific validity. To strengthen their stand these scientists also claim that CO2 emission by man through out human history constitute less than 0.00022 percent of the total naturally emitted from the mantle of the earth during geological history. To them, temperatures of the Earth have often been warmer than now with higher CO2 levels through out the Earth’s history. Further, the phenomenon of rising sea level is not new. It has been going on since ice age some 10,000 years ago. It is myth that receding glaciers are proof of global warming, as glaciers have been receding and growing cyclically for many centuries. There is no scientific or statistical evidence whatsoever that global warming will cause more storms and extreme weather events. It is myth that CO2 is the most common greenhouse gas that is responsible for the present global warming because CO2 constitutes mere  0.037% of the total 3% greenhouse gases in the atmosphere. It is rather the sun which is responsible for the greater share of climate change. To them, increase in atmospheric content of CO2 and relative increase in global warming is more beneficial to human beings than cold climate. Therefore, the proposed limits on greenhouse gases emissions by the IPCC would harm the environment, hinder the advancement of science and technology, and damage the health and welfare of mankind.
          On the other hand, the other group of scientists represented by Intergovernmental Panel on Climate Change (IPCC) claimed that Earth’s climate is warming faster than normal. Since the 1950s, the rate of global warming has been unprecedented compared to the previous decades and millennia. The average increase in the Earth’s temperature during the period has been 0.85 degrees Centigrade.  IPCC finds the increase in the global temperature with 95% scientific certainty due to excessive release of greenhouse gases mainly CO2 by man during the period. The CO2 atmospheric concentration in 2019 is above the line of 400 ppm (parts per million) whereas the same  had never been above the line of 300 ppm till 1950.   Secondly, IPCC have observed that global sea levels have risen faster than at any time during the previous two millennia due to increased melting of land-based ice, such as glaciers and ice sheets and warming of the ocean.  The oceans have also absorbed much of the increased heat thereby making sea water warmer than before.  Thirdly, the Asia region as a whole have been observed the most weather and climate related disasters in the world between 2000 and 2017 due to the changing behaviour of Asiatic Monsoon caused  by changing rainfall, melting snow or ice worldwide. IPCC have also observed receding of Himalayan Glaciers faster than in any part of the world. It also has observed that the Greenland and Antarctic ice sheets have been losing mass in the last two decades and that of the Arctic sea and Northern Hemisphere as well. Unequivocal Warming of the atmosphere and ocean system  has been observed and sea level change is unprecedented since 1950. The Earth’s global surface temperature for 2016 was 1.43 degree centigrade (2.57 degree F) above the 20th century average, surpassing the previous record of 2015 by 0.11 degree C (0.19 degree F) and became the warmest year since modern record keeping began in 1880. It is extremely likely that anthropogenic influence has been the dominant cause of all the above observed warming since 1950. Lastly, IPCC have pointed out that the longer we wait to reduce our emissions, the more expensive it will become.
          It is observed from the above that although 97% of the scientific community of IPCC have consensus on the human-caused global warming theory as the dominant factor for the present global climate change, over 400 prominent scientists from more than 24 countries openly dissented the IPCC theory. Further, the signing of the Petition Protest against the IPCC theory by more than 31,847 scientists worldwide till march 2008 and the endorsement of the petition by the famous scientist Frederick Seitz, past president, of National Academy of Sciences, U.S.A. clearly cast doubt on the claim of the IPCC. However, almost all the scientists worldwide have unanimously agreed upon the unprecedented rate of global warming since the 1950s compared to the previous decades and millennia. But, this unusual rate of warming is due to human or not is still a matter of strong debate at least in the US where the issue is highly politicised.
The author is Chairman of Safe Environment Campaign Committee