Climate change is a long-term change in the earth's climate, especially a change due to an increase in the average atmospheric temperature. Recent warming of the climate means that there is more energy available in the atmosphere and ocean waters to fuel tropical storms. The graph showing the total number of storms in the North Atlantic shows that a warming of global temperatures this has had a recent impact on the FREQUENCY number of moderate to long lived storms. We have also seen an increase in the number of short duration storms that are hurricane intensity for 2 days or less.
What has increased due to warmer temperatures has been the INTENSITY of the storms experienced. The trend line on the graph shows that accumulated storm energy is clearly going up over time. Stronger winds like this will result in greater damage to human property and unfortunately higher STORM SURGES, (huge waves of water pushed up onto the land) which kill the majority of people that die in tropical storm events.
The DISTRIBUTION of tropical storms is also predicted to change. The map shows where we will experience changes in the Power Dissipation Index. Significant areas around the globe will experience stronger storms, and some of those areas are outside of the current areas were ocean temperatures go above 27 degrees C.
So in summary, although the number of storms has not gone up, the strength or intensity of the storms is going up and these storms are affecting more parts of the globe, thanks to warmer temperatures due to climate change.