An article in the Houston Chronicle on Sunday, provided a great example of the current issues that are hampering cities’ climate adaptation planning. I discussed this issue in an earlier blog post about the adaptation gap. The adaptation gap is the difference between adaptation efforts and adaptation need. This gap is largely a result of uncertainty by key decision makers regarding the impact of climate change on their communities.
This adaptation gap is on full display in the Chronicle article. Harris County and City of Houston officials, responsible for flood mitigation and stormwater management for the region, are reluctant to take any significant action toward flood mitigation infrastructure because of uncertainty of future flood events. Their rationale is that this community is prone to extreme events, both floods and droughts, and it is not possible to say that climate change will have any significant impact on these events in the future. Harris County and the City are waiting on more evidence before they feel it is necessary to invest a whole lot more in flood mitigation efforts. An additional study to better understand the climate and weather linkage is underway.
On the other side, you have insurance companies and climate scientists arguing we have more than enough evidence that climate change is making weather events more extreme. Some good examples are the Global Risk Report of 2016 and Munich RE’s Natural Catastrophe Services which reported 160 North American insurance loss events, the most since 1980. Also, according to the National Flood Insurance Program, all but 2 of the last 15 most expensive flood insurance programs have happened since 2000. Five of the 15 happened in the Houston region. This includes Hurricane Ike #3; Tropical Storm Allison #9; Hurricane Rita #11; Memorial Day Flood #14 and the Tax Day Flood #15. The total is about $5 billion in flood insurance payouts for these events.
Further, the Louisiana 1000 year flash floods, in August 2016, was recently studied by a team from NOAA that demonstrates a strong linkage between climate change and extreme weather events. According to this study, climate change increased the intensity of these storms by 10% and the likelihood of this storm occurring by 40%. Further, even without these specific event studies, basic understanding of the hydrological cycle would indicate that there is a higher likelihood of extreme flooding events on the horizon in a wet climate like Houston’s. Texas Tech University Climate Scientist Katharine Hayhoe, quoted in the Chronicle article, does a great job explaining how we are seeing an increasing number of extreme weather events in her Global Weirding video series.
However, even with this mounting evidence, there is a disconnect. The information is still not being communicated in a way that allows key decision makers to feel less uncertain about climate change and more willing to invest the political, human and financial capital to adapt. Both public and private sector decision makers need to have a better idea as to the climate risks they are facing in the near and long-term. The ambiguity around future outcomes makes it difficult to identify appropriate strategies to manage future risk. Also, there is a gap between available scientific information and the demand for information framed in the context of risk and uncertainty making it difficult to make decisions. There are many cases where risk assessments and climate impact studies provide range of outcomes, but with little information on their probability distributions. When budgets are tight and political capital is hard to come by, making decisions based on a range of outcomes is difficult. The role for scientists and climate change communicators is to make these decision makers feel they have more actionable information. This requires that what is communicated is not the standard line that “you are going to have a lot more flooding in the next 20 years.” A city cannot do anything with this information. Rather it should be more , “there is a 75% change your community will experience 5-6 500 year floods in the next 10 years.” The city can then weigh its other risks and obligations against this information and take action. This can be done and it needs to be done, if we want cities to take the necessary steps to adapt their communities for climate change.
(As a side note, Dr. Hayhoe was was in Houston to speak at HARC’s People and Nature Speaker Series. She is returning to Houston on April 30. She has done a great job with several cities in helping them better understand their risks to climate change. The City of Chicago is a good example.)