It is sad that leaders across the world remain insensitive to the huge risks from climate change faced by the weak and the poor. There are major equity considerations in the current reality of climate change
The world has seen a series of extreme events in recent months, with three successive hurricanes hitting the Caribbean and North American region; unprecedented forest fires in California; and now parts of Europe and the east coast of the US in the grip of a severe cold wave.
It is no surprise that US President Donald J Trump, the high priest of climate sceptics and someone who is surprisingly immune to scientific knowledge, tweeted, “In the East, it could be the COlDEST New Year’s Eve on record. Perhaps we could use a little bit of that good old Global Warming that our country, but not other countries, was going to pay TRIllIONS OF DOllARS to protect against. Bundle up!”.
It was in 2011 that the Intergovernmental Panel on Climate Change (IPCC) brought out a special report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX). Climate change must be understood as not merely an increase in temperature but a major disruption of the climate system, which has been relatively stable for almost a million years.
Some have described the current era as anthropocene, since human activities are now the major determinant of the geological, ecological and climatic conditions of this planet. Thomas l Friedman, the distinguished columnist of the New York Times, rightly refers to global warming as “global weirding”. Essentially, what he is trying to convey is the fact that globally, the climate is becoming weird.
President Trump’s sarcastic comment through the well-established erudition of his tweet can easily be demolished with a very simple scientific explanation. With increase in surface temperature on land and bodies of water, there is an increase in evaporation. This results in much heavier quantities of water being held in the atmosphere in the form of clouds. When it rains or snows, therefore, the quantity of precipitation is substantially higher than would have been the case if there was no warming of the earth’s surface.
In other words, if we go back to pre-industrial times, when the quantity of carbon dioxide in the atmosphere was around 280 parts per million (ppm) and not in excess of 400 ppm as is the case today, temperatures would have been lower. Consequently, the extent of evaporation would also have been lower. The blizzards which have currently hit the eastern parts of North America and parts of Europe have occurred on account of extreme precipitation.
The fact that this has come in the form of snow, and with much lower temperatures can also be explained by the fact that warming is taking place across the globe and this has a major impact on the movement of air from one region to the other. The current cold spell in North America and Europe is the result of cold air moving from the Arctic region southwards, which would normally not have happened with the stability of air currents in the Arctic region.
Of course, any single extreme weather event cannot be attributed to human induced climate change, because there are several other factors which can account for extreme weather conditions. However, the increase in atmospheric moisture content would be expected to lead to an increase in extreme precipitation when other factors do not change.
The IPCC in the Special Report referred to the above concluded that since 1950, it is very likely that there has been an overall decrease in the number of cold days and nights, and an overall increase in the number of warm days and nights at the global scale, that is, for land areas with sufficient data. There is evidence of the likelihood of such changes having occurred at the continental scale in North America, Europe and Australia.
There is also a warming trend in daily temperature extremes in much of Asia. Very reliable climate models, which are validated on the basis of past records of climate, project substantial warming in temperature extremes by the end of the 21st century. It is virtually certain that increases in the frequency and magnitude of warm days and nights and decreases in the cold days and nights will occur through the 21st century at the global scale. This is mostly linked to mean changes in temperatures, although changes in temperature variability can play an important role in some regions. It is very likely that the length, frequency, and/or intensity of warm spells or heat waves (defined with respect to present regional climate) will increase over most land areas.
For a set of plausible emission scenarios of the future a one-in-20 year annual hottest day is likely to become a one-in-two year annual extreme by the end of the 21st century in most regions, except in the high latitudes of the Northern Hemisphere where it is likely to become a one-in-five year annual extreme.
There are major equity considerations in the current reality of climate change and projections for the future. Typically, developing countries are the most vulnerable to these extreme impacts of climate change, but, unfortunately, they also lack the capacity and infrastructure to be able to withstand them.
In very simple terms, a cyclone in Bangladesh causes much greater havoc than a hurricane with the same intensity which hits the state of Florida. That part of the US, which receives several hurricanes, just as Bangladesh is subjected to a large number of cyclones, has extremely reliable and timely early warning systems, and it is not uncommon to see large numbers of people just nailing boards of wood on their windows and escaping to safer areas away from Florida. Such a possibility does not exist in Bangladesh, and the risk to life and property is, therefore, substantially higher.
Another aspect of human induced climate change and its impacts in the form of higher frequency and intensity of extreme events is the possibility of the same location being subjected to two or more dissimilar extreme occurrences.
The same place, therefore, could suffer from drought conditions during some period of a year and then heavy precipitation during another period in the same year. This would compound the problem of steady water supply and storage. California has just suffered from a tragic mudslide, which is the result of extreme precipitation and recent loosening of soil with trees having burnt down due to prolonged forest fires, aided by dry weather and high temperatures.
It is sad that leaders across the world remain so insensitive to the huge risks from climate change faced by the weak and the poor and their own children and grandchildren wherever they would be on this planet.
(The writer is former chairman, Intergovernmental Panel on Climate Change, 2002-15)