What is the Scientific Basis of Climate Change?

In his new encyclical Laudato Si’, Pope Francis declares “that [t]he climate is a common good” and observes that [a] very solid scientific consensus indicates that we are presently witnessing a disturbing warming of the climatic system.” One of the elite scientists who advises the Holy Father as a member of the Pontifical Academy of Sciences is Dr. Veerabhadran (Ram) Ramanathan. Last week we began providing excerpts from a summary of a position paper written by Dr. “Ram,” entitled “The Two Worlds Approach to Mitigating Climate Change: The Top One Billion and the Bottom Three Billion.” We continue in this week’s Update.

The Scientific Predictions: By early 1980s, studies predicted that the warming will be accompanied by increased humidity in the air, get amplified in the polar regions, melt sea ice and continental glaciers and would penetrate to the deeper oceans and increase sea level, among other changes (Charney, 1979). The famous Charney report was followed by a prediction that the warming due to manmade greenhouse gases would become discernible by 2000 (Ramanathan and Madden 1980), which indeed was verified by a team of about 500 scientists assembled by the United Nations (IPCC, 2001). This 2001 report concluded: ‘An increasing body of observations gives a collective picture of a warming world and other changes in the climate system’, and ‘There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities.’ The predictions about polar amplification of the warming, melting of arctic sea ice and sea level rise were all confirmed by data.

Is it Climate Change or Climate Disruption?

The only difference was that in most instances the observed changes were much larger than the predicted changes. The strongest warming was observed since the 1970s. The planet has warmed by about 0.850C (1.50F) and the last decade was the warmest decade since James Watt’s time. The arctic warming is three times as much, threatening the ecology of the region. The warming was accompanied by increasing occurrences of severe weather such as heat waves, intense hurricanes, mega droughts and floods, which came as a surprise to the climate science community for it had not predicted the intensity of the extreme events. This has led to the emerging view that we should think of it not as global warming or climate change but as climate disruption (a term now used by some policy makers in the UN).

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