More Lightning In Our Future?

Nov 26, 2014 By Aarathi
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We have all heard of the effects of global warming on climate change, ice sheets and sea levels. Now, it appears that rising temperatures can affect lightning too.

According to atmospheric scientists, a one degree Fahrenheit increase in global temperatures could spark off a 7% increase in lightning strikes!

To put it in another perspective, if temperatures continue to rise as predicted, by the year 2100 there will be 50% increase in lightning strikes over the previous century.

How Lightning Forms

To understand this, let’s look at how lightning occurs. Electrical storms form when warm, moist air mixes with cold, icy air. Warm, moist air is light and rises like steam from a pot of boiling water. Cold, icy air is heavy, and slowly sinks like mist settling on the ground.

When these two types of air meet in a cloud, the water molecules intermingle like pedestrians on a busy street—bumping, shoving, and occasionally, exchanging an electron. But they don’t exchange electrons equally. The warm air discharges more electrons. The sinking icy air typically ends up with the stole-away-electrons, and the warm air continues up, now positively charged.

This creates a charge build-up within the cloud. When there is an imbalance of positive or negative charge, this is called static electricity. When the cloud can’t hold the charge anymore, it releases it in the form of lightning!

The Effect Of Global Warming

A warm atmosphere can hold more moisture.  Global warming directly contributes to greater moisture (water vapor) in the air and is therefore more conducive to thunderstorms and lightning. The levels of moisture and an unstable atmosphere (which allows air to rise) are both necessary conditions to build lightning.

Lightning is more common in certain tropical and temperate regions of the world. However, continental USA (especially the south-east) receives 30,000 lightning strikes a year. Scientists predict that for every 2 lightning strikes today, the U.S can expect to receive 3 lightning strikes by 2100.

Lightning is responsible for more than half the wild-fire blazes in the United States. Containing them is not easy at all because the location cannot be predicted and is often quite far from fire stations. Lightning also changes the composition of greenhouse gases in the atmosphere – it reduces methane, but produces more ozone.

Scientists will continue studying how the atmosphere's composition changes with temperature. But if there is one takeaway for us, it is the realization that we are responsible for the world we leave behind for future generations. 

Courtesy National Geographic, BBC