Saturday, August 17, 2013

Fires and Floods

Robertscribbler attributes massive fires in Russia, followed by an immense rainstorm and flood, to the effects of climate change:
Earlier this year, drought and heatwaves blanketed Siberia and Yakutia. But late July, this region had begun to erupt in a series of extraordinary wildfires that blanketed almost all of northern and eastern Russia in very dense smoke. By early August what is perhaps the worst rainstorm in the history of this area of Russia had begun to form. As of the writing of this article, on August 14, major storms and flooding continued with no immediate end in sight.
Major heatwaves and droughts in extreme northerly regions of Siberia are an anomalous event linked to human caused climate change. Rapid sea ice and snow cover retreat combine with temperatures that are warming at a rate of .5 degrees C each decade over this region to increase the likelihood of such extreme events. Methane and organic carbon stores in the thawing tundra steadily release under this heat forcing and likely provide an amplifying feedback to summer heating events by locally providing more greenhouse gas emission and also providing another fuel store that is available to wildfires. In some of these wildfires, there are reports coming in that fires burn as far as 3 feet into the ground, taking out root systems and stumps along with the trees that burn above ground. Reports of burning ground have also been trickling in (Hat tip to Colorado Bob)
Such burn events are anomalous enough. But for a flood that covers a 1 million square kilometer area to immediately follow in the wake of such amazingly large and widespread fires is anything but normal. Atmospheric patterns that link major weather systems and increase their intensity can be attributed to the formation of powerful heat dome high pressure systems along with weakened and meandering Jet Stream waves. Rising atmospheric heat caused by human warming adds to the density and strength of heat domes (identified as becoming more intense by meteorologist Stu Ostro). Meanwhile erosion of the Jet Stream caused by reduced snow and sea ice cover (identified by Dr. Jennifer Francis) is implicated in a host of problems including more intense and persistent droughts and storm events along with the increased likelihood that weather systems will link up as north to south weather patterns deepen, back up, slow down, and elongate.
A massive ocean heat dome to the south over the Pacific adjacent to China and sea ice and snow cover remaining near record lows must be taken into account when looking at features that likely contributed to the extreme swings from drought, heatwave and fire to massive deluge and flood in Russia.
One last point to consider as a likely contributor is the fact that for each degree (Celsius) of human-caused temperature change, the hydrological cycle amplifies by about 8 percent. This means that rates of evaporation and rainfall are now about 6 percent more intense than they would be in the world of the 1880s. When combined with powerful new weather features like a mangled Jet Stream and immense heat dome high pressure systems, an amped up hydrological cycle further inflates an already extreme environmental condition.
 The impacts of extreme weather will continue to grow.  As we reach a carbon dioxide tipping point things will get crazier yet.

No comments:

Post a Comment