Climate Change Tests Metropolitan Resilience With Wider Array Of Weather Dynamics
Well, with humanity having so reshaped the planet's surface and atmosphere these past decades and centuries, what were once outliers in probability are becoming more routine. Yes, fewer people die in disasters today than in decades past - something like 98% fewer people compared to 1900! But the costs and the dislocations are clearly rising with serious speed. Per the US Global Change Research Program's recent National Climate Assessment Assessment, we can cite the following extreme-weather trends:
As the world has warmed, that warming has triggered many other changes to the Earth’s climate. Changes in extreme weather and climate events, such as heat waves and droughts, are the primary way that most people experience climate change. Human-induced climate change has already increased the number and strength of some of these extreme events. Over the last 50 years, much of the U.S. has seen increases in prolonged periods of excessively high temperatures, heavy downpours, and in some regions, severe floods and droughts ...
Heat waves are periods of abnormally hot weather lasting days to weeks. The number of heat waves has been increasing in recent years. This trend has continued in 2011 and 2012, with the number of intense heat waves being almost triple the long-term average. The recent heat waves and droughts in Texas (2011) and the Midwest (2012) set records for highest monthly average temperatures. Analyses show that human-induced climate change has generally increased the probability of heat waves., And prolonged (multi-month) extreme heat has been unprecedented since the start of reliable instrumental records in 1895 ...
Heavy downpours are increasing nationally, especially over the last three to five decades. The heaviest rainfall events have become heavier and more frequent, and the amount of rain falling on the heaviest rain days has also increased. Since 1991, the amount of rain falling in very heavy precipitation events has been significantly above average. This increase has been greatest in the Northeast, Midwest, and upper Great Plains – more than 30% above the 1901-1960 average. There has also been an increase in flooding events in the Midwest and Northeast, where the largest increases in heavy rain amounts have occurred.
One measure of heavy precipitation events is a two-day precipitation total that is exceeded on average only once in a 5-year period, also known as the once-in-five-year event. As this extreme precipitation index for 1901-2012 shows, the occurrence of such events has become much more common in recent decades ...
The mechanism driving these changes is well understood. Warmer air can contain more water vapor than cooler air. Global analyses show that the amount of water vapor in the atmosphere has in fact increased due to human-caused warming.,,,This extra moisture is available to storm systems, resulting in heavier rainfalls. Climate change also alters characteristics of the atmosphere that affect weather patterns and storms ...
Flooding may intensify in many U.S. regions, even in areas where total precipitation is projected to decline. A flood is defined as any high flow, overflow, or inundation by water that causes or threatens damage. Floods are caused or amplified by both weather- and human-related factors. Major weather factors include heavy or prolonged precipitation, snowmelt, thunderstorms, storm surges from hurricanes, and ice or debris jams. Human factors include structural failures of dams and levees, altered drainage, and land-cover alterations (such as pavement) ...
There has been a substantial increase in most measures of Atlantic hurricane activity since the early 1980s, the period during which high quality satellite data are available.,,These include measures of intensity, frequency, and duration as well as the number of strongest (Category 4 and 5) storms. The recent increases in activity are linked, in part, to higher sea surface temperatures in the region that Atlantic hurricanes form in and move through. Numerous factors have been shown to influence these local sea surface temperatures, including natural variability, human-induced emissions of heat-trapping gases, and particulate pollution. Quantifying the relative contributions of natural and human-caused factors is an active focus of research ...
Winter storms have increased in frequency and intensity since the 1950s, and their tracks have shifted northward over the United States., Other trends in severe storms, including the intensity and frequency of tornadoes, hail, and damaging thunderstorm winds, are uncertain and are being studied intensively. There has been a sizable upward trend in the number of storms causing large financial and other losses. However, there are societal contributions to this trend, such as increases in population and wealth.
All this is to say that US metropolitan areas should expect to suffer weather "freak-outs" on a far more consistent basis in coming years and decades - over a far wider array of dynamics. Right now we're witnessing such a freak-out in the Washington DC area, and, I can tell you, having lived there for years myself, it is indeed a freak-out primarily because local, state and federal agencies there simply don't put in the time and effort to work these extreme winter storms (either in advance or during) and because so much of the population living there is un-experienced in navigating their way amidst such conditions. And yet, it grows ever more obvious that major US metro areas will be forced to deal with such extreme-weather events on a far more regular basis, meaning those skills will need to be developed and honed - by everyone throughout the government, society, and economy.
Per the NOAA chart above, we will measure these events primarily in damages incurred (private insurance, publicly-funded reconstruction) and lost economic activity (business continuity), and yes, that is a huge improvement over the age-old statistic of lives lost. But we are talking about metropolitan governments needing to be "masters" of so many more "domains" over time that it's clear there will need to be a lot more transparency, planning, and preparation efforts jointly pursued by private and public-sector entities.
You know the old joke about a conservative being a former liberal who once got robbed? Well, a resilience-aware executive/political leader is oftentimes simply someone who's had to answer for a weak response to an extreme-weather event.
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