Professor Michael E Mann (Pennsylvania State University )
[climate change] exacerbated several characteristics of the storm in a way that greatly increased the risk of damage and loss of life. Climate Change worsened the impact of Hurricane Harvey.
Sea level rise attributable to climate change – some of which is due to coastal subsidence caused by human disturbance such as oil drilling – is more than half a foot (15cm) over the past few decades (see here for a decent discussion). That means the storm surge was half a foot higher than it would have been just decades ago, meaning far more flooding and destruction.