Storm clouds have been getting bigger and moving closer to the poles according to Carolyn Gramling in Science:
“Since the 1980s, the world has gotten cloudier toward the poles and less cloudy in the midlatitudes; towering thunderclouds have also gotten a bit taller.
“Those patterns matched three rather dire climate model predictions: that storm tracks – the paths along which cyclones travel in the Northern and Southern hemispheres – would shift poleward; that subtropical dry regions would expand, and that the tops of the highest clouds would get even higher. All of these changes can worsen global warming.”
At lower latitudes, storm clouds serve to reflect heat back into space. By moving toward the poles, they allow more solar radiation to warm land and sea in tropical regions. Taller storm clouds also have a blanketing effect, trapping more heat at higher latitudes.
If the observed patterns are a global warming trend, then they add to the likelihood of our overshooting the 2C upper limit set in the Paris Agreement. However, since 1980s, two volcanoes – Mexico’s El Chichon in 1982 and the Philippines’s Pinatubo in 1991 – had a large impact on cloud formations. Further research is ongoing to disentangle the effect of the volcanoes from those of our changing climate.