Thunderstorms and climate change UPSC

A Thunderstorm, a captivating weather phenomenon, unfolds when towering cumulonimbus clouds take center stage, accompanied by the awe-inspiring duet of lightning and thunder. The typical repertoire of a thunderstorm includes robust and gusty winds, copious rainfall, intermittent hail, and, in extreme cases, the menacing touch of tornadoes.

Globally, a staggering 2000 thunderstorms unfold concurrently, unleashing a torrent of approximately 100 lightning strikes per second and a jaw-dropping 8 million lightning strikes every day. The fundamental recipe for a thunderstorm is deceptively simple: a blend of moisture, rapidly ascending unstable air that persists in rising when nudged, and a catalyst to set the process in motion. This catalyst can be provided by weather fronts, sea breezes, mountains, or even the cool outflow from a preceding thunderstorm, aptly termed a gust front. This orchestration of elements initiates the birth of a new thunderstorm.

While thunderstorms are more prevalent in the spring and summer, thriving on the essential ingredients of warmth and moisture, the afternoon and evening hours become their preferred stage for performance. However, winter occasionally unveils the intriguing spectacle of thundersnow, a rare scenario where thunderstorms unfold, and snow (or graupel or hail) gracefully descends instead of rain.

Climate Change and Thunderstorms

Enter the stage of climate change, where rising global temperatures become the conductors of an evolving symphony in the atmosphere. As the climate warms, the air becomes a more accommodating host for moisture, holding approximately 7% more moisture for every 1°C of warming. This heightened moisture content sets the scene for a heightened drama of thunderstorms, ushering in more potent storms and an amplified chorus of lightning strikes. The consequence? Intensified downpours contributing to localized flash flooding.

Read Also: Tornado, Definition, Rotation, Formation, Frequency,location, Diagram

A scientific revelation published in the journal Science forecasts a 12% surge in lightning activity for each 1°C of warming. This implies a substantial 50% increase in the number of lightning strikes by the end of the century, a formidable shift that countries like the USA may have to grapple with.

Yet, the impact of climate change on thunderstorms introduces a nuanced complexity. As seasonal norms undergo transformations, certain regions may experience a decrease in the number of storms—a pivotal consideration for areas reliant on these storms for agricultural sustenance.

The Dichotomy of Severe Thunderstorms

Beyond the ordinary spectacle of thunderstorms lies a more formidable force — severe thunderstorms. Characterized by sustained winds exceeding 93 kilometers (58 miles) per hour or the presence of unusually large hail, these atmospheric juggernauts have the potential to birth perilous supercells, derechos, and tornadoes. At the heart of their formation are two pivotal architects: convective available potential energy (CAPE) and strong wind shear.

The Dramatic Duo: CAPE and Wind Shear

CAPE serves as the metric for the raw energy available to storms, intricately linked to the warmth, moisture, and buoyancy of the air. Simultaneously, wind shear gauges the nuanced alterations in wind speed and direction with increasing altitude. In the words of Harold Brooks, a distinguished meteorologist at NOAA’s National Severe Storms Laboratory, “CAPE can provide storms with the raw fuel to produce rain and hail, and vertical wind shear can pull and twist weak storms into strong, windy ones.”

Climate Change Choreography

As the narrative of climate change unfolds, a complex dance between warming surfaces and shifting wind patterns takes center stage. The warming surface, by infusing more moisture into the air, amplifies CAPE. Yet, a counterpoint emerges with disproportionate warming in the Arctic, potentially mitigating wind shear. this paradox sets the stage: one factor enhances the likelihood of severe storms, while the other may temper their ferocity.

Decoding the Climatic Enigma

The arena of climate modeling becomes the battlefield where researchers strive to decode the intricacies of this climatic enigma. Led by Robert Trapp of Purdue University, a compelling study suggests that a doubling of greenhouse gases could usher in a significant escalation in the frequency of severe thunderstorms in the southern and eastern United States. Cities like Atlanta and New York may find themselves grappling with a doubled count of days conducive to severe thunderstorms.

Visualizing the Climatic Tapestry

The vivid tapestry painted by climate models, comparing the summer climate in 2072–2099 with the period from 1962–1989, showcases a forecasted surge in CAPE potentially outweighing a slight decrease in vertical wind shear. this delicate imbalance portends an increase in severe thunderstorms, particularly in regions such as Missouri and the coastal areas of North and South Carolina. the Southeast emerges as the epicenter of heightened CAPE, while the Mountain West contends with the most pronounced decrease in wind shear. Consequently, the eastern United States stands on the precipice of a more substantial increase in days conducive to severe thunderstorm formation compared to its western counterpart.

The Atmospheric Saga Unfolds

As the curtain rises on this atmospheric saga, the symphony of thunderstorms and their severe counterparts unfolds, underscoring the intricate interplay between climate change and the dynamic theater of the skies. In this evolving drama, the architects of CAPE and wind shear determine the fate of atmospheric intensity, leaving a lasting imprint on the climatic narrative of our changing world.