A heat dome has settled over the Pacific northwest, extending into Canada and stretching as far south as Las Vegas, Nevada. It is not unusual for temperature records to be broken by a degree or so. This time they are being shattered.
In some places previous records have been exceeded by as much as 10 degrees F, and scientists note this has no precedent in modern record-keeping. Portland, Oregon reached an all-time high of 116 degrees F, least expected in a place known for a moderate climate. Just a little north and inland, Lytton, British Columbia recorded an almost unbelievable 121 F (49.6 Celsius) on June 29, 2021, setting a new record for Canada as a whole. The previous high for Lytton, which had stood since 1941, was surpassed by 9F.
While one cannot ascribe individual extreme events to global warming, scientists expect their frequency to increase. Also a warming globe is going to raise the temperature of sea water. This causes more evaporation into the atmosphere forming more clouds and thunderstorms, and it also increases the probability that hurricanes and typhoons will develop. So the reasoning goes.
Another consequence of the warming is sea level rise (SLR). It happens in two ways: higher temperatures heat and expand the water itself and, secondly, melt ice sheets as over Greenland and the Antarctic. A new study published in Nature Communications this weekprojects the threat of SLR on global coastal communities in numbers of people affected and comes up with the startling figure of 410 million.
Perhaps the threat is being realized already, as seawater seepage is one theory for the partial collapse of the 12-story condominium in Surfside (a suburb of Miami, Florida). Last week on June 24th at 1:05 am, a part of the building simply slid down burying the sleeping residents in a pile of rubble. It is possible the seepage weakened the foundation by destabilizing the soil until the foundation buckled.
Another theory focuses on the construction and the reinforced concrete. Beach sand tends to be contaminated with salt, and, according to this theory, when used in the concrete, it accelerates corrosion of the iron rebars which will fail, weakening the concrete. Worse still, engineers have discovered from the wreckage that damaged columns appear to have less steel than the design drawings required.
Modern concrete can last a 100 years when properly maintained (which is expensive) but can break down in half that time and repairs can cost more than the original cost. For example, Frank Lloyd Wright’s celebrated Fallingwater, a home built near Pittsburgh has cantilevered balconies over a waterfall — it is a dramatic design thanks to reinforced concrete. Completed in 1939, it requires continual expensive maintenance on the concrete, and despite this major repairs had to be undertaken in 2002 to prevent structural collapse. The cost of all this is of course several times the original construction cost.
Florida is not the only state suffering coastal threats. In Texas, a $26 billion plan modeled on Dutch dikes has been passed by the legislature to protect the Galveston region. Yet with global warming, the threat of rising seawater levels for coastal communities all over the world is only likely to get worse.
