by Paul Beckwith
In recent months we have endured incredible tropical-equatorial-like torrential rain events occurring at mid-latitudes across the planet. For example, in North America we experienced intense rainfall in the Banff region of the Rockies from June 19th to 24th and the enormous volume of water moved downhill through the river systems taking out small towns and running into the heart of Calgary where it caused $5.3 billion dollars of infrastructure damage; the largest in Canadian history.
Next, it was Toronto’s turn, with 75 mm of rain falling from 5 to 6pm on July 8 (with up to 150 mm overall in some regions) leading to widespread flooding and $1.45 billion dollars in damages. As bad as these events were, they were dwarfed by the intense rainfalls hitting the state of Colorado from Sept 9th to 15th.
Rainfall amounts that would normally fall over 6 months to a year were experienced in less than a week. Widespread flash floods, landslides, and torrents of water ripped apart roads, fracking equipment and pipelines on (at least) hundreds of fossil fuel sites (mostly ignored by mainstream media) (http://www.desmogblog.com/2013/09/19/media-ignores-damaged-oil-and-gas-tanks-colorado-floods). The level of destruction was simply horrifying, as captured by a man with a plane and a camera. But we have no grounds for complaint, since the widespread flooding in central Europe from May 30th to June 6th caused a much larger $22 billion in damages.
So what is happening? Why are we experiencing so many of these severe weather flooding events that are supposed to only occur every 1000 years or so? Will they keep occurring? What city will be hit next? Can the Alberta tar sands be hit by such an event? What would be the implications?
Abrupt Climate Change In Real-Time
In a nutshell, the logical chain of events occurring is as follows:
- Greenhouse gases that humans are putting into the atmosphere from burning fossil fuels are trappingextra heat in the earth system (distributed between the oceans (93%), the cryosphere (glaciers, ice sheets, sea ice for 3%), the earth surface (rocks, vegetation, etc. for 3%) and the atmosphere (only an amazingly low 1%). The oceans clearly get the lions share of the energy, and if that 1% heating the atmosphere varies there can be decades of higher or lower warming, as we have seen recently. This water vapor rises and cools condensing into clouds and releasing its stored latent heat which is increasing storm intensity.
- (i)Rapidly declining Arctic sea ice (losing about 12% of volume per decade) and (ii)snow cover (losing about 22% of coverage in June per decade) and (iii)darkening of Greenland all cause more solar absorption on the surface and thus amplified Arctic warming (global temperatures have increased (on average) about 0.17oC per decade, the Arctic has increased > 1oC per decade, or about 6x faster)
- Equator-to-Arctic temperature difference is thus decreasing rapidly
- Less heat transfer occurs from equator to pole (via atmosphere, and thus jet streams become streakier and wavier and slower in west-to-east direction, and via ocean currents (like Gulf Stream, which slows and overruns continental shelf on Eastern seaboard of U.S.)
- Storms (guided by jet streams) are slower and sticking and with more water content are dumping huge torrential rain quantities on cities and widespread regions at higher latitudes than is “normal”.
- A relatively rare meteorological event called an “atmospheric river” is now much more common, and injects huge quantities of water over several days to specific regions, such as Banff (with water running downhill to Calgary) and Toronto and Colorado events.
For a notion of whiplashing, consider the Mississippi River. There were record river flow rates from high river basin rainfall in 2011, followed by record drought and record low river water levels in December, 2012 making it necessary for the U.S. Army Corp of Engineers to hydraulically break apart rock on the riverbed to keep the countries vital economic transportation link open to barge traffic. Then, 6 months later, the river was back up to record levels. Incredible swings of fortune.
Mitigation at a global level is dysfunctional and inadequate
Adaption has not worked out too well for Calgary, or Toronto, or Colorado, or numerous other places. Let us not be surprised when a similar torrential rain event hits Ottawa, or Vancouver, or even the Alberta tar sand tailing ponds. In Alberta, tailings ponds would be breached and the toxic waters would overflow the Athabasca River and carry the pollutants up into the north to exit into the Arctic Ocean. Such an event would be catastrophic to the environment and economy of Canada.
How can this risk be ignored? Will the latest IPCC (Intergovernmental Panel on Climate Change) report AR5 released on September 27th once again be ignored by society?
Paul Beckwith is a part-time professor with the laboratory for paleoclimatology and climatology, department of geography, University of Ottawa. He teaches second year climatology/meteorology. His PhD research topic is “Abrupt climate change in the past and present.” He holds an M.Sc. in laser physics and a B.Eng. in engineering physics and reached the rank of chess master in a previous life.
No comments:
Post a Comment