Connection between global warming and droughts is very intuitive. Yes, heat leads to droughts. Yet, linkage between global warming and storms or floods is not so obvious. It is understandable that when the earth is hotter, glaciers melting will cause sea level to rise. Nevertheless, that sounds like a very gradual and adaptable progress. Why storms, sudden floods and all the weather-related damages we see on the TV from time to time?
A closer look at direct consequences of global warming reveals its indirect connection to storms and floods. Firstly and obviously, global warming causes glaciers in Greenland and the arctic to melt which rises the sea level. Physically, in higher temperature, water also expands, effectively increasing the volume of the current sea water. As the temperature goes up, water also evaporates more. On top of that, hot air is capable of holding more water vapor. The latter two properties combined mean that there is more water in the air, which is the necessary condition for heavy rainfall and the build-up of storms. In addition, a study by NASA asserted that as a result of global warming, there is higher frequency of extremely high clouds, which are directly linked with formation of storms. The same study suggested that with the current rate of temperature change, there will be 6% more storms every decade. Finally and probably most importantly, a rise in sea surface temperature helps to sustain and intensify storms after they are formed. The energy in this warm water helps storms travel further distance and cause greater damages. In a nutshell, increase in global temperature, through many processes and feed-back processes, causes storms and floods to happen more often and with greater severity.
As a resident of Vietnam, I have seen increasingly frequent and devastating storms. Vietnam is a tropical country with 3444 km coastline. This natural location makes it prone to tropic storms and floods (video embedded of a common street flood). In 2006, there were 10 typhoons in the region with three directly affecting Vietnam. In 2007, the number of direct hits increased to 6. Every year hundreds of people are killed during these typhoons in Vietnam. When I was in high school in 2006, we had three days off because of a storm going onshore in my province, which is usually not affected. People in the area were advised to put rocks on their tin roof, which is popular in Vietnam, to prevent it from being blown away in strong winds. Some neighbors sent their children to sleep with us for the night because my house was just rebuilt at that time so was supposed to be more weather-proof. That night went by slowly as we anxiously waited for the storm to be over while listening to the increasing death statistics on the radio.
At the time I did not link floods and storms to global warming, or think about them as human-caused disasters. I thought they were just natural phenomenon that we had to deal with. Yet, global warming has been proved to increase those disasters. Pointing out the link between storms and global warming helps demonstrate the urgent and severe nature of the situation, prompting countries to act and reduce their environmental impact.
