Lawmakers must pay heed to Nicholas Stern and others warning that existing estimates could be just a fraction of actual costs.
A study by Climate Central, a US-based climate news organisation, warns that many millions more will be affected by rising sea levels because of climate change than previously estimated. Published in Nature Communications, the findings are based on correction of biases in elevation (from the sea level) datasets that were previously used to estimate how far inland the coastline will shift. For instance, the dataset generated by the orbiter Endeavour’s radar that mapped heights across the globe is widely-used. But, Climate Central researchers posit that this data suffers from biases—in areas with thick vegetation, the radar has picked up the canopy, rather than the ground, as the surface —that make the land look higher than it actually is. The revised elevation data finds that, even with moderate reductions in greenhouse gases’ emissions, six Asian nations, including India, could face annual coastal flooding by 2050; 36 million Indians risk loss of home and livelihood by 2050, compared with 5 million estimated earlier.
Given our limited understanding of climate change and its physical impacts, it is difficult to predict its economic impact. But, as eminent researchers—including economist Nicholas Stern, who, in 2006, came up with one of the most widely-cited estimate of the economic costs of climate change—state in a paper brought out recently by the Grantham Rsearch Institute of Climate Change, The Earth Institute at Columbia University, and Potsdam Institute for Climate Impact Research, existing estimates of the economic impact of climate change don’t account for many risks; thus, the fallout could, in fact, be much higher. In 2015, Stern had said that even the assessments and estimations by the Inter-governmental Panel on Climate Change (IPCC) fall way short of the accurate estimate given they “simply do not reflect current knowledge about climate change and its potential impacts on the economy.” Now, in the Grantham-Earth Institute-Potsdam paper, the authors say that “economic assessments of the potential future risks … have been omitting or grossly underestimating many of the most serious consequences for lives and livelihoods”. There are many uncertainties plaguing estimation of economic costs, from cascading effects of one or more major impact, some of which could be irreversible or unstoppable, to the potential inability of humans to adapat to certain impacts. These will undoubtedly undermine growth and development, fundametnally setting back remediation. Economic assessments, the researchers say, “fail to take account of the potential for large concurrent impacts across the world that would cause mass migration, displacement and conflict, with huge loss of life”, and often “use inappropriate discounting”. Moreover, there could be unanticipated risks because scientists may not have even detected their possibility.
In his 2006 paper, Stern had claimed that unabated climate change could cost at least 5% of the GDP annually, and the costs of reducing emissions could be limited to 1% of global GDP. He had estimated that 200 million people globally would likely be permanently displaced by the mid-21st century. The Climate Central research now claims that by that time, coastal floods could expose nearly 237 million people from just six Asian countries to this threat. In 2016, Stern had told The Guardian that he had “underestimated the risks” in his 2006 report, and “should have been much stronger … about the costs of inaction”. Policymakers and business leaders can now ill-afford an ostrich-like attitude towards climate change. They must pay heed to Sterns’ warning that models that assume catastrophic damages are not possible, or underplay their chances of occurring, “fail to take account of the implications of the science.”