Are Tropical Cyclones Getting Worse?

     Harvey has rekindled the debate between climate change advocates and deniers over whether tropical cyclones are becoming more frequent and intense.  Both sides tend to overstate their respective cases.
     Trying to get a handle on whether these storms are getting worse is not as easy as it might seem.  First, exactly how you measure the intensity of a storm is somewhat problematic.  Hurricane Sandy, which caused extensive damage to the East Coast and was frequently referred to in the media as a “superstorm,” was only a Category 1 storm on the Saffir-Simpson scale.
     The Saffir-Simpson scale is exclusively determined by wind speed.  [Click here for discussion of the scale.]  But we have learned that wind speed is just one factor in determining the severity of a storm and the resulting damage.  For example, the physical size of the storm is another important indicator of its tidal surge.  And, of course, the resulting damage from any storm is largely determined by where it makes landfall and the population and property in its path.  Had Sandy made landfall along a coastline with far less population, no one would have referred to it as a “superstorm.”
     Another problem is that the farther we go back into historical records, the less accurate the information is about the incidence and the severity of the storms.  Since the 1960s we have had reliable data from satellites.  But that is the blink of the eye on the scale of climate history.  Before that, the data is much less accurate, relying frequently on incomplete narrative accounts and spotty meteorological observations.
     Nonetheless, the National Weather Service has compiled a list of tropical cyclones that have occurred in the Atlantic basin since 1850, based on the best information they have.  They have categorized the storms into three categories: tropical storms, hurricanes and major hurricanes.  Click here to see the table.
When you graph this table, it looks like this:
    The upward trend is pretty clear, at least, on this most global level of the data.  And the 2017 data will tilt the trend lines a bit higher since this has been such an active season.

If we look only at all the storms that reached tropical storm status since 1970, the trend line flattens out significantly, supporting the notion that there is an observational bias before 1970 that under counted storms.  The trend is still up but it is considerably less dramatic than the hyperbole we frequently hear from climate change advocates.

     Of course, history is not necessarily a predictor of the future.  But these trend lines significantly undermine those who argue that the current spike in storms is nothing more than a naturally recurring weather cycle.

Weather events, by their nature, are episodic and tend to be cyclical.  There are lots of highs and lows.  Climate change advocates cherry pick the highs to bolster their case and climate change deniers do the same with the lows.

I think there are two conclusions we can draw from the data.

First, tropical cyclones do appear to be getting somewhat worse.  You can attribute that to climate change or not, but the best bet going forward is that we need to prepare for more frequent and intense storms.  However, there is little in the historical record to support a prediction that the increase will be dramatic.[1]

     Second, storms of relatively similar strengths are causing much more damage now than in the past because there are so many more people and so much more property in their paths.
Both of these conclusions support policies that would better prepare our coastlines to withstand storms and to mitigate their impact.  That means building structural protections, improving flood control, adopting better building codes, being more careful where we build things and restoring natural features that dampen the impact of the storms, e.g., wetlands and oyster reefs.
     While pursuing policies which will reduce carbon emissions is a laudable goal, there is no evidence that policies to that end will have any short or medium term effect on reducing the frequency or severity of tropical cyclones.
     Of course, it is not an “either-or” choice.  We can work to make our coast lines more resilient and to reduce carbon emissions at the same time.  But if the goal is to reduce the impact of tropical storms in the short or medium term, we need policies primarily aimed at strengthening our coastal defenses.

[1] The issue of whether tropical cyclones are getting worse and the effect of climate change on tropical storms is a topic that is hotly debated within the meteorological community.  Ryan Maue, a well-known climate change denier, has made the case that frequency and intensity of tropical cyclones has actually declined in recent years. [Click   here to see his data and argument.]  However, the conclusion that storms are gradually getting more frequent and intense represents the consensus opinion of the meteorological community.  [Click here.]
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Two Flood Bills Died in Legislature

Two bills were introduced in the last Legislative session to study flooding in the Houston region.  Both died in committee.

SB1269 was authored by State Senator Boris Miles and co-sponsored by Senators John Whitmire and Sylvia Garcia.  The bill would have authorized $1.5 million to establish and fund a task force to complete a “comprehensive flood control infrastructure study.”  Not exactly bold leadership, but to the Senate’s credit SB1269 was approved unanimously.

But it never saw the light of day in the House.  When it was received by the House from the Senate it was referred to the Natural Resources Committee.  There is no one from the Houston region on that committee.  No member of the Houston delegation picked up the bill.  The committee held about a five-minute perfunctory hearing.  Representative Armando Walle appears to have been the only Houston area representative to speak in favor of the bill.  The bill was “left pending” in the committee at the end of the session.

Senator Larry Taylor introduced SB2265, which would have restructured an existing entity to give it the power to begin constructing a coastal spine system to protect the region from storm surges.  But the bill did not authorize any funds and was contingent on the federal government funding the entire project.  It, too, was approved by the Senate unanimously.

In the House, SB2265 was referred to the Special Purpose Districts Committee, which is chaired by Representative Jim Murphy.  Representative Wayne Faircloth, from Galveston, filed a companion bill, HB4308.  There are notations that these bills were heard briefly in committee, but both were also left pending at the end of the session.

These bills were utterly inadequate compared to the challenges that our region faces from flooding.  They really called for nothing more than additional studies.  To paraphrase Mark Twain, there has been so much research on this subject “it is probable that if they continue we shall soon know nothing at all about it.”

But the fact that our Legislature could not even pass these watered-down (excuse the pun) measures is pathetic.  Of course, the Legislature had time to argue about all manner of nonsense in this session, but when it came to actually doing something about one of the most persistent threats to our region, they took a powder.

The threat of large scale flooding from either a storm surge or massive rain events, such as what we just experienced, cannot be effectively addressed solely at the local level.  The scope of these events exceeds the jurisdictional limits of any single municipality or county.  While there is certainly a role for local entities, we also need a regional approach.

Ideally, Governor Abbott should call a special session to deal with this problem.  At a minimum, we need a robust interim study so the Legislature is prepared to immediately take action on flooding in our region when the Legislature meets again in 2019.

The time for shuffling our feet and thinking about maybe studying this problem is over.  Now is the time for action.
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Time to Tap the State Rainy Day Fund for Regional Flood Projects

The State of Texas prudently maintains a “Rainy Day” fund.  Currently the fund balance is just over $10 billion.  The technical name for the fund is the Economic Stabilization Fund.  Either of its monikers strongly suggest that it should be tapped at this time to jump start critical flood control projects in the Houston region.

Our region is subject to two types of flood risks.

The first is a storm surge from a hurricane.  A storm surge from a “Scenario 7” storm, a Category 4 or larger that makes landfall near Freeport, is an existential threat to our region.  Such a storm would flood all of Galveston County, about half of Brazoria County and about 20% of Harris County.  It would kill thousands, cause billions in property damages and inestimable ecological damage as the surge overruns sites with decades of industrial pollution.  It would also wreak havoc on the State and national economy as a large percentage of the refining and petrochemical capacity would be offline for months.

The second risk is from massive rain events which outstrip our drainage system’s ability to move the rainwater to the Bay.  Of course, the recent Harvey flooding was an extreme example of such an event.  These events are occurring more frequently because we are getting more rain than we have in the past and because we poured concrete and asphalt over soil that used to soak up some of that rainfall without making adequate provision for the resulting increased runoff.

The good news is that there are solutions to both problems.  The bad news is that the solutions are expensive. . . . and I mean really expensive.

The solution to storm surge flooding is a coastal barrier, as originally conceived by Texas A&M Galveston’s Bill Merrill, and subsequently refined by input from a variety of stakeholders.  The cost is $10-15 billion.

The solution to Harvey-type flooding is more multifaceted and probably still requires some additional study.  But it clearly must include shoring up the Barker and Addicks reservoirs, adding massive amounts of additional detention, tightening up detention regulations and building codes, and potentially building a third reservoir.  The costs for these measures is less certain but could easily be another $5 billion.

I am not suggesting we should drain the Rainy Day fund to build these projects.  Most of the tab will have to be picked up by the Federal government.  But the Federal government gives preference to projects where local and State governments are willing to pick up a share of the costs.  If our State leadership goes to the Feds with a commitment to use some of the Rainy Day fund, say $2 billion, we will stand a much better chance of getting Federal funding.

If we fail to address these risks there will be long-term adverse economic consequences for our region, the State and indeed the entire nation.  The Houston region accounts for almost 30% of the State’s total GDP.  As goes Houston so goes the State.

After a week of nonstop national news coverage about how vulnerable Houston is to flooding, what corporation is going to relocate here?  Would you schedule a convention in Houston during hurricane season?  How many companies are going to build a new plant in a place where it could be inundated by a 25-foot storm surge?

Now is the time for bold leadership, not Republican primary posturing.  There is nothing conservative about failing to make investments that we know are needed to avoid future losses.  In fact, it is grossly irresponsible not to do so.

A hundred years from now no one is going to remember anything about bathroom bills or even know what that the hell a sanctuary city was.  But, as we remember the construction of the Galveston Seawall over a century after it was built, our grandchildren will remember whether we, as a generation, stepped up and ended the threat of devastating flooding to our region and the State’s largest economic engine.