J. Clim. https://doi.org/10.1175/JCLI-D-19-0461.1 (2019)

The strength and likelihood of atmospheric convection is often distilled into two quantities. Convective available potential energy (CAPE) estimates the energy that air can access if lifted to a height where it is buoyant; more CAPE suggests a less stable atmosphere and stronger convection. Convective inhibition (CIN) is the energy that air must overcome to access its CAPE; higher CIN implies that air is more stable and less buoyant. Both CAPE and CIN are expected to increase over land under climate warming. Understanding why informs future storm behaviour.

Jiao Chen of Nanjing University, China, and co-authors use climate models to analyse these warming-induced increases. Over most land, higher CAPE is attributed to more moisture in the near-surface atmosphere, which releases extra latent energy as air rises and water condenses. CIN increases are due to lower near-surface relative humidity, which makes it more difficult for rising air to condense water and release latent heat. These changes lead to a recipe for more extreme weather: while higher CIN suppresses storms and increases dry-spell and drought likelihood, higher CAPE permits more vigorous convection and heavy precipitation.