How did climate change impact Hurricane Harvey? While no single weather event can be caused by climate change, scientists agree that warmer temperatures helped create a cocktail of conditions essential for this catastrophic storm. Craig Welch of National Geographic interviewed a multitude of climate scientists and boiled it down to three defining factors that made Harvey truly fierce: (1) rapid intensification, (2) record amounts of rainfall and (3) stalling over East Texas.

Here’s a quick summary of how climate change may have influenced each:

• Rapid intensification: Although hurricanes typically weaken as they approach land, Harvey grew much stronger in the last 24 hours before landfall. Hurricanes are powered by the evaporation of seawater, which essentially happens much faster when it’s warmer. Scientists believe that warmer air and ocean temperatures in the Gulf – caused by climate change –  likely contributed to Harvey’s last minute intensification. 
• Record amounts of rainfall: Warmer temperatures also increased the amount of moisture that Harvey could hold and churn out in record levels of rainfall across East Texas.
• Stalling: The connection between climate change and the final ingredient – Harvey’s stall over land – is less clear. Weak winds around the storm have enabled the storm to hover and continue feeding off of warm moisture from the Gulf. However, there is not enough evidence yet to determine the role of climate change in the steering of storms.