Controversy

The consensus

The scientific community around climate change has increasingly worked on the link between global warming and hurricanes’ behaviors. Since Hurricane Katrina (cat. 5) in 2005 causing tremendous human and material damages on the American soil, publications flourished on this type of extreme event, especially among the American scientists.

Recently we are witnessing an emerging consensus among the climate scientists vis-à-vis the correlation between climate change and intensity of hurricanes. According to the Intergovernmental Panel on Climate Change (IPCC) Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX – 2012), tropical cyclones will become less numerous but stronger. Seemingly, « it is likely that the average maximum wind speed of tropical cyclones (also known as typhoons or hurricanes) will increase throughout the coming century, although possibly not in every ocean basin. However it is also likely—in other words there is a 66 per cent to 100 per cent probability—that overall there will be either a decrease or essentially no change in the number of tropical cyclones » All scientists recognize that there are too few reliable data on the hurricane history to be able to see clear trends of an anthropogenic influence on the behavior of hurricanes. Statistics on hurricanes are considered to be accurate only since 1970 (even sooner in some basins). If measurement techniques have greatly improved recently, it makes it difficult to compare the data and to detect trends.

This finding is therefore acknowledged in the IPCC SREX : « uncertainties in the historical tropical cyclone records, the incomplete understanding of the physical mechanisms linking tropical cyclone metrics to climate change, and the degree of tropical cyclone variability provide only low confidence for the attribution of any detectable changes in tropical cyclone activity to anthropogenic influences ». Thus, we may not be able to see the effect of global warming on the behavior of hurricanes before several generations.

An intense debate led to these conclusions. Although the scientific community agrees, controversies around the measurement of hurricanes’ change of behavior appeared and many issues rose. Some voices were heard on the lack of trustworthiness considering the tools, data and measuring models that are used to evaluate the impact of climate change over hurricanes, and the focus on the Atlantic pool by the American scientists clearly leads to a downscaling of the research. Lastly, a lot of different scientific domains were gathered around this controversy, and brought up new factors that were ignored so far, that are economic and demographic.