# Ajayan | A week into the monsoon, with thunder and gusty winds disrupting the season’s usual calm, climatologists are attributing this shift to global warming. Even steady rains, they note, have failed to lower rising temperatures.

Since the start of monsoon on May 24 till May 30, Kerala received 395.5 mm rain, against a normal of 69.6 mm, a departure of 468 per cent. Kannur topped with a departure of over 850 per cent.

Rain accompanied by thunder and lightning is typical during summer showers or the Northeast monsoon (Thulavarsham) from mid-October. However, the presence of intense thunder even after days of torrential downpour that has submerged parts of Kerala signals, climatologists say, just how overheated the planet is becoming.

A shift in cloud characteristics is becoming increasingly evident. Typically, the monsoon brings cumulus clouds; shallow, widespread formations driven by moisture-laden winds from the Arabian Sea, with atmospheric humidity hovering around 70%. As warm air rises, condensation occurs rapidly, forming these clouds with limited vertical depth and base height. Crucially, such clouds are not associated with lightning activity.

For lightning to occur, clouds must have significant vertical development, allowing electrical charges to build; positive at the top and negative at the base for discharge. During summer, when winds bypass direct moisture transport from the Arabian Sea, humidity levels are lower. As a result, clouds must ascend to greater heights before reaching condensation and saturation. This leads to the formation of towering cumulonimbus clouds, often stretching from a 2 km base up to 12 km high, creating ideal conditions for lightning.

Rising global temperatures have intensified convection, driving the formation of more volatile weather systems. Climatologists note that a 1 degree Celsius increase in temperature boosts the atmosphere’s water-holding capacity by about 7%. The result: cumulonimbus clouds, capable of discharging lightning, now often develop alongside traditional cumulus formations, leading to episodes of intense rainfall accompanied by dramatic thunder and lightning.

With global warming now an undeniable and enduring force pointing toward intensification, the skies are poised to grow more volatile. The , once rhythmic and predictable rainfall often gets laced with thunder and lightning.