This week main news is the flooding of Housten by Hurricane Harvey. Michael E. Mann discusses the links to climate change here.

The factors involved are:

  1. Sea level rise - coastal subsidence, mainly due to oil drilling, have increased to ca. 15 cm over the last few decades. This means storms surges are higher than previously and thus flooding worse over larger areas.

  2. Sea surface temperature rise - In the region sea surface temperature have risen around 0.5C giving 3% - 5% increase in atmospheric moisture, creating potential for much greater rainfalls and greater flooding.

  3. Deep water temperature rise - as warming penetrates down into the ocean creating larger layers of warm deep water feeding the hurricanes.

  4. Changed weather patterns - Harvey stalled at Houston for several days as prevailing winds failed to steer it off to the sea - due to greatly expanded subtropical high pressure over great parts of the US with the jet stream pushed up north - a weather pattern where both high-pressure dry hot regions and low-pressure stormy/rainy regions stay locked in place for many days at a time article.

Conclusion: Man-made Climate Change worsened the impact of Hurricane Harvey.