Climate change in the tropical Pacific and its influence on Atlantic hurricanes
The number of tropical storms per year in the Atlantic varies considerably from year to year, with El Niño being one major factor. When the eastern Pacific Ocean warms up, Atlantic hurricanes tend to be suppressed (and vice versa for La Niña). As the climate warms due to greenhouse gas emissions, hurricanes are expected to change. Such changes could include the average number of storms per year, where they tend to form, how strong they become, how far and fast they travel, how much rain they produce, and how El Niño affects them. However, one of the least certain aspects of future climate is the warming of the eastern tropical Pacific Ocean. In this talk, I will give a brief overview of the current state of the field aimed at understanding the response of the tropical Pacific to climate change, followed by a presentation of a recent study using CESM2 to investigate how the formation regions of Atlantic tropical storms may change in the future, particularly as a function of eastern Pacific warming. We find that the warming of the eastern Pacific strongly influences predictions of future changes in Atlantic hurricanes, including how El Niño affects them. Specifically, a strong eastern Pacific warming causes a change in the vertical structure of zonal winds over the tropical Atlantic, which shifts where hurricanes will tend to form in the future and increases the effect of El Niño. I will close by discussing the broader implications for uncertainties in projections of hurricanes and coastal risk.