Sea-level rise: The ostrich approach to climate adaptation

One of the key questions addressed in the Fourth National Climate Assessment is one of timing: When will the U.S. begin to feel the impacts of global warming?

The answer is unsettling, because it's past tense. We've been seeing the impacts, in the form of hotter and longer-lasting heat waves as well as sea-level rise and more frequent coastal flooding, for years.

Why it matters: We're not responding in the ways climate experts hope we will, at least not yet.

"This is a risk management problem par excellence," said Princeton's Oppenheimer. "We would have to be incredibly irresponsible" not to take action in light of what is known about climate change, he said, speaking of both adaptation to climate impacts today and emissions cuts.

The trends: According to a new report from Climate Central and the real estate data firm Zillow, in more than 50% of coastal states, homes are being built at a faster rate in areas at risk of flooding from sea-level rise than the rate of new homes in safer areas.

• Overall, they say about 386,000 current coastal U.S. homes are expected to be at risk of regular flooding by 2050, because of rising seas caused mainly by climate change.
• With increased sea-level rise through the year 2100, 2.5 million homes — worth $1.3 trillion — would be subjected to regular flooding if emissions continue to increase unchecked.
• Harris County, Texas, home to Houston, is building homes in flood-prone areas at 1.4 times the rate that it is building homes in non-flood-prone areas.
• On the other hand, Brunswick County, North Carolina, is building homes in flood-prone areas at 1/5th the rate as in non-flood-prone areas.

"It’s difficult to plan for higher seas if you are busy digging deeper holes," said Benjamin Strauss, CEO and chief scientist of Climate Central, in a press release.