Open Ocean Home

Our news

Latest updates on Open Ocean's activities and news from the marine energy sector

Hurricanes and climate change

For the past few weeks, one question is on everyone's mouth: Is there a relation between climate change and the recent repetition of very strong hurricanes events in the Caribbean and US South-East? The experts say that it is not the easiest question to answer.

Over the months of September and October, four hurricanes went over the Caribbean and the US Southeast: Harvey, Irma, Maria and José. This is the usual hurricane season, hence should not be so surprising. However, what struck most people is that two out of four of these hurricanes were category 5 hurricanes, and they appeared over just the span of four weeks.

Hurricanes grow and thrive on the energy provided by warm ocean waters. This is the reason why they tend to appear after the northern hemisphere summer during which surface ocean temperatures rise significantly.

Hurricane-en.svg.png

Global climate change having already increased the overall ocean surface temperature, there could be a simple link to be made between the global trend and the recent extreme events.
Scientists tell us right away that this link is not so obvious....

The main explanation is that the birth of hurricanes does not just rely on the sea surface temperature but also on the atmospheric temperature vertical gradient, and the winds at high altitudes. As the atmospheric temperature vertical gradient has barely been affected by climate change, it is likely that we will not see an increase in the number of hurricanes, and maybe even a decrease.

Indeed, according to the IPCC (Intergovernmental Panel on Climate Change)  and their climate simulations of the 21th century, the cyclones will decrease in their frequency but will be more intense in terms of rain and wind. For instance, at its peak, Irma’s hurricane sustained maximum wind speeds of at least 185 mph for 37 hours, more than has ever been recorded for a storm. It is the first hurricane which remained as a category 5 for that long.

GraphHurricanes.png

The forecasted trend give us some insight but unfortunately, we are lacking a long history of hurricanes characteristics to fully understand where we are currently standing on that trend. Before the 1970’s and the implementation of a complete network of satellites which is analyzing the earth constantly, we do not have access to precise data about hurricanes characteristics all along their lifecycle.

Hurricane impact on populations

The recent extreme events have struck our conscious by the impact on the population but it is always important to dissociate weather from climate. These events happening in a row could be part of a trend, but we’ll need many similar events over several years to call it a trend. Two points on a graph can define a straight line, but as soon as you’ll add a third point, it could totally change the trend direction. There is no more doubt for global climate change, but its direct impact on hurricanes occurrence and intensity can not be seen yet.

Hence, we have to carefully differentiate our feelings from seeing the population hurt and the science of hurricane. Especially because the impact of these type of events will surely keep increasing.
One has to keep in mind that more and more populations live close to the coasts in the United States. This will always increase the density of population and housings, hence the destruction resulting from hurricanes. Political decisions with respect to building permits could make a difference on the impact of hurricanes along the coast, especially as these coastal areas are also affected by the rising sea level.

The meteorological warnings coming from improved weather forecasting surely helped saving lives. However, for the Caribbean islands population obviously limited in land space, only very large investments in more resistant infrastructure will make a difference. Let’s hope that the international aid would come in to help with engineering such that it does not have to bring as many tents, food and water bottles after the events.

Open Ocean has developed an innovative methodology to produce more accurate extreme value analysis of metocean parameters at sites affected by hurricanes.

Contact us to learn more about this new methodology.