PARIS • Scientists say the devastating intensity of hurricanes such as Harvey is consistent with global warming trends - rising seas, warming oceans, hotter air - and warn of "bigger and stronger" storms to come. Here are their answers to questions about the link between climate change and tropical storms, known variously as cyclones, hurricanes and typhoons.
Q Does warming bring more cyclone rain?
Kerry Emanuel, professor of atmospheric science, Massachusetts Institute of Technology "The rarity of hurricanes, coupled with the difficulty of measuring rainfall, makes this highly problematic. Harvey's rainfall near Houston is more like a thousand-year event. But we expect hurricane rainfall to increase substantially this century as a consequence of warming oceans and atmosphere." Stefan Rahmstorf, co-chair, Potsdam Institute for Climate Impact Research "A logical consequence of global warming is a global increase of extreme rainfall events. In the case of Harvey, it is the heavy rain - and the resulting flooding - which is the greatest threat. A global increase of daily rainfall records is indeed seen in the rainfall observations. This trend will continue as long as we keep pushing up global temperatures by emitting greenhouse gases."
Q Is the poleward shift of cyclones significant?
Kerry Emanuel "In the poleward migration, we see a definite climate signal that matches our expectations... We think that as the century progresses, places that are on the poleward margins of hurricane zones (for example, Japan and New England) may experience more frequent and more intense hurricanes." James Kossin, scientist, US National Oceanic and Atmospheric Administration's Centre for Weather and Climate "The poleward drift - 53km per decade in the Northern Hemisphere, and 62km in the Southern - is highly relevant to society - arguably as much as changes in intensity. Places that are more accustomed to these storms and are better prepared for them may see less exposure, but places that are less well prepared may see more."
Scientists say Harvey is consistent with global warming trends - rising seas, warming oceans, hotter air - and warn of "bigger and stronger" storms to come.
Q Will cyclones change in the future?
Kerry Emanuel "We expect that Category 3, 4, and 5 storms will become more frequent globally as the climate warms. But this will vary from place to place. Some places may even see a decrease." Jeffrey Kargel, professor, University of Arizona "Whether we can attribute Harvey to global warming - as with any individual weather event - is a questionable proposition. But it is very likely that many more storms like Harvey and Katrina and bigger ones yet are on the way."