Super Cyclones and Climate Change: Understand the connection

Extreme weather events are on the rise globally, with devastating effects on people and infrastructure. Evidence is mounting that human-induced warming is contributing to increased frequency and intensity of several types of extreme weather events, including torrential downpours, and coastal flooding. These trends are expected to continue – with associated damages worsening – in an increasingly warmer world.

Climate change increases the probability of some types of weather. Recent heavy rains and floods globally are consistent with a warming planet, and such events are expected to become more common over time.

As average temperatures have gone up globally, more rain has fallen during the heaviest downpours. The average August 2014 temperatures recorded manifest the increasing trend in global temperatures as indicated below:

• The global land surface temperature was 0.99°C above the 20th century average of 13.8°C, the second highest on record for August, behind 1998.
• For the ocean, the August global sea surface temperature was 0.65°C above the 20thcentury average of 16.4°C. This record high departure from average not only beats the previous August record set in 2005 by 0.08°C, but also beats the previous all-time record set just two months ago in June 2014 by 0.03°C.
• The combined average temperature across global land and ocean surfaces for August 2014 was record high for the month, at 0.75°C above the 20th century average of 15.6°C, topping the previous record set in 1998.

It is interesting to note the world’s ocean temperatures are warmer than they were few decades ago. This increases the chance of major storms. When oceans reach warmer temperatures, more of it evaporates, priming hurricane or cyclone formation. Once born, a cyclone or hurricane needs only warm water to build and maintain its strength and intensity.

Very heavy precipitation events, defined as the heaviest one percent, now drop 70 percent more precipitation than they did 30 years ago. This happens because warmer air holds more moisture. For each one degree Celsius rise, the atmosphere holds 5-7 % more moisture. This fact is apparent when you see water vapor hanging in the air after turning off a hot shower. When warm air holding moisture meets cooler air, the moisture condenses into tiny droplets that float in the air. If the drops get bigger and become heavy enough, they fall as precipitation.

The recent decade has seen an exceptional number of high-impact extreme weather events such as Cyclones, typhoons, hurricanes, flash floods on big scale across the globe covering all the continents. The most important aspect of these big events is the frequency of occurrence. Once in a decade extreme weather event has become once in a six- month normal event across the globe.

So instead of asking who has been responsible for global warming and the consequent big weather events like Super cyclones, here are the most important takeaways—all of which have significant implications for decision-makers and society:

Humans are largely responsible for rising global temperatures

75% of the 20th century increase in the atmospheric greenhouse gases such as water vapor and carbon dioxide is directly caused by human actions like burning Petroleum products (hydrocarbon fuels) for energy needs. The green house gases retain the heat in the earth’s atmosphere and the heat trapped by greenhouse gases in the atmosphere gets absorbed by oceans. The warmer oceans are the source of devastating cyclones, typhoons and hurricanes.

Cutting green house gas emissions is the most urgent imperative for reducing frequency of big weather events

What’s needed is bold action by the world’s leaders. To ensure a relatively safe and stable climate, we must enact new policies that drive economic investment into low-carbon technologies, reduce global emissions, and enhance the resilience of our communities and critical infrastructure.

This requires urgent action: Our energy systems will have to fully decarbonize for clean energy solutions like Nuclear and Solar for all the energy needs from industrial, household to Public transportation.

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Written by Rajesh Kumar ​Pothula​