New studies from the International Atomic Energy Agency (IAEA) researchers showed that climate change does not only affect the severity or amount of rain but also the precipitation patterns.
According to Al Gore, the founder of the Climate Reality Project, since warmer air holds more moisture, rising global temperatures also contribute to the changes in rain patterns, including rain’s occurrence, duration and distribution. Gore also stated that global water vapor increases by 7% for every degree centigrade of warming.
Climate change can affect two types of rain – stratiform and convective. Convective rain, which occurs more frequently, is sudden, intense and local. Meanwhile, the stratiform type is lighter and can fall over a larger area for a longer time.
Isotopes as clues
In June 2016, hydrology specialist Pradeep Aggarwal and his co-authors announced that the oxygen and hydrogen isotopes in rain samples provided data on the ratio of these two rain types.
Isotopes are atoms of the same element that have different numbers of neutrons that result to different atomic weights. The condensation and evaporation of water affect the ratio of heavy to light isotopes.
Observing and understanding how the water cycle responds to climate change is difficult and critical. These findings could also contribute to a better understanding of how climate change affects rainfall patterns, which could later help in adaptation and precipitation models in the future.
Rainfall and Climate Change
As temperatures rise, air becomes warmer. Hence, more moisture evaporates from land and water into the atmosphere. More moisture in the air means more precipitation and heavy downpour.
The problem is that extra rain is not evenly distributed throughout the globe. Because of the shifting air and ocean currents brought by climate change, some countries may receive more or less precipitation than others. According to the US Environmental Protection Agency (EPA), the world is already getting more rain and snow than it did a century ago.
Looming La Niña
PAGASA and other international meteorological agencies confirmed a 55 to 60% probability of La Niña development in the last quarter of 2016. La Niña is the unusual cooling of ocean temperatures in the Central and Eastern Equatorial Pacific.
Because of this weather phenomenon, more active rainfall activity is expected in Southeast Asia, including the Philippines. PAGASA said that after the sweltering dry months, we are now anticipating slightly cooler and wetter months ahead.
Rising temperatures triggered by climate change and the previous El Niño episode may begin to decelerate due to La Niña. According to the University of New South Wale’s Climate Change Research Center, a rise in global temperatures may still occur, but it won’t be as rapid as what had been observed last year.
US Climate Prediction Center
International Atomic Energy Agency
University of New South Wale’s Climate Change Research Center
US Environmental Protection Agency