Via Nature News & Comment: Did climate change cause Typhoon Haiyan? Excerpt:
Are such storms getting worse in a warming world?
This is the million-dollar question, but there is not yet a scientific consensus on how to answer it.
Storms receive their energy from the ocean, so it would seem logical that they would get stronger, and perhaps also more frequent, as the upper layers of tropical oceans get warmer. The potential intensity of tropical storms does increase with warmer sea surface temperatures. However, the effect of warming seas could be counteracted by the apparent increase in the strength of shearing winds — winds blowing in different directions and varying in strength at different altitudes. Shearing winds tend to hinder the formation of storms, or tear them apart before they can reach extreme strength.
On balance, many climate researchers think that it is plausible that tropical-storm activity will rise as the planet warms. There is some evidence that storm intensity has increased over the last three decades, but reliable data are limited to the north Atlantic, where observations are most abundant. In other places, the evidence is not yet conclusive.
The Intergovernmental Panel on Climate Change (IPCC) in its latest report cautiously summarizes the current state of knowledge:
“Time series of cyclone indices such as power dissipation, an aggregate compound of tropical cyclone frequency, duration, and intensity that measures total wind energy by tropical cyclones, show upward trends in the North Atlantic and weaker upward trends in the western North Pacific since the late 1970s, but interpretation of longer-term trends is again constrained by data quality concerns.”