Whether anthropogenic climate change has affected the nature, intensity and frequency of natural disasters? It used to be a polarising issue in the scientific community. Not anymore, it is becoming more and more evident that climate change driven primarily by human activities is changing the pattern and intensity of natural disasters.
The World Meteorological Organisation (WMO) released a comprehensive report of extreme weather events and disasters in the past fifty years and it clearly shows that extreme weather events have grown five times in the last fifty years. Despite the rise in the instances of natural disasters, the amount of people dying from disasters has consistently decreased. Thanks to better predictions and early warning systems, facilitated by advancements in technology and efficient disaster management, the amount of people who died in the last decade is one-third of the number that died fifty years ago from natural disasters.
A more nuanced look at the data of natural disasters reveals some interesting and alarming facts. Droughts and storms were the biggest killers in the second half of the last century. Although the reports of occurrence of droughts are about one-sixth compared to those of storms or floods, they still managed to kill twice as many people as floods did. Instances of floods on the other hand have increased as compared to previous decades but the number of people dying has consistently decreased. The only disaster for which the number of reports and deaths roughly vary linearly is storms.
Upon observing the data it seems that what kills people is the kind of disaster whose effects can’t be localised. For example, floods– can be predicted easily, happen at specific sites mostly along rivers and evacuation is possible for even very extreme situations; sure it still results in heavy economic losses. Same with landslides and wildfires, they happen and people die by accident not by some spiralled out long sustained effect.
Drought is a good example of how a less occurring natural disaster that has a slow onset can kill so many people, although, now the number of deaths are miniscule. Drought is just a normal cyclic process which produces prolonged dry periods, it cripples agriculture, biodiversity and the economy of a region. Although droughts still happen but less people die because the world is more organised to avert losses due to such disasters, there is an efficient food supply chain which helps replenish any shortages around the world, sending emergency help and emergency use medication is quick and easy. Also the global economy functions in a way that a disaster at one place ends up affecting everyone in some way, unlike the 1970s-80s when the world was more contained and also polarised.
Reported deaths from all kinds of disasters have decreased, except one– extreme temperature event. Reports of high temperature events were non-existent until the 1990s and deaths went from negligible in the 1990 to the second most lethal disaster in the 2000s. Extreme temperature events are different from all other disasters, they cannot be predicted very reliably and they are not localised. It is impossible to evacuate people because temperatures are rising, extreme temperature events stress electricity supply as people turn up air conditioning and in underdeveloped or low-income countries it stresses the healthcare systems. As of now, 2016 was the hottest year on record, and the warmest seven years have all been after 2015. The rising temperature will not only make many places uninhabitable but also affect crop yields across the globe, which is a major concern because world’s population is about to peak sometime in the second half of this century and keeping aside supply chain disturbances, a fall in the yield at major agricultural activity sites may lead to starvation and political upheaval.
According to a paper which studied the potential crop yield loss for different RCP (Representative Concentration Pathway) levels, the crop yield is expected to drop by 5.6% for RCP 2.6 (which is the lowest projected scenario and corresponds to an increase in global mean temperature by 1.5 - 2 degree celsius); for RCP 8.5 (corresponds to an increase in global mean temperature by near +4 °C) the projected losses are 18% assuming the losses in crop yields decrease linearly with each degree increase in mean global temperature. There are three major crops that the world depends on for calories– wheat, maize and rice; all of them are grown in a very localised manner in specific spots around the globe i.e. the top five crop producing countries generally produce more than 50-60% of all crops. Projections predict that for rice there will be a 3% decline in yield for each degree rise in temperature, 6% for wheat and for maize it will be 7.4%. As the effect of rising temperature will be most prominent on regions near the equator, India is at risk of suffering a decline in its crop production. India is one of the largest producers of maize and wheat, it is projected to lose 9.1% of wheat production, 6.6% of wheat and 5.5% of wheat yield for each degree rise in temperature.
India this year banned the export of wheat to keep domestic prices in check because there was a fall in domestic output. Ukraine, one of the largest producers of wheat, is battered because of Russian invasion and countries are cautious of importing anything from Russia because of the economic sanctions on the country and also because it has developed a negative image on the global platform after invading a sovereign nation.
The disasters that are localised in their scope, that the world has learned to handle, are causing more economic losses than they did before, especially in developed countries, mostly because they have better infrastructure in place that can be damaged. The number of deaths is still higher in developing and low income countries as compared to developed ones, but it has consistently been going down, across all countries. But the ones that have stretched out consequences are getting more serious.
Given that the world is clearly going to miss an RCP 2.6 scenario– for that the carbon dioxide and methane emissions needed to start declining by 2020, and we are far from it– the threat of hunger and extreme temperature events is only going to inflate. The inevitable rise of sea levels accompanied with a growing population is going to create a serious refugee problem in the coming decades.