(Image source: NSIDC)
According to reports from NSIDC, Greenland ice sheet melt had exceeded average summer maximum values by Tuesday, June 11th, about a month and a half earlier than normal.
On Tuesday, about 24% of the Greenland ice sheet had experienced melting. This value is about 1% higher than the usual summer maximum of 23% melt coverage.
2013’s early, widespread melt follows just one year after melt covered nearly all the Greenland ice sheet for days during July of 2012. 2012’s melt was the strongest for Greenland in at least 120 years. For 2013 melt values to approach or meet 2012 melt values would further reinforce a powerful increase in Greenland melt that has occurred since the 1990s. Since that time, the rate of Greenland melt has more than tripled.
June 2013 has established a trend of rapidly increasing melt that sets in place conditions for past record values to potentially be challenged. As such, it is well worth monitoring conditions as they develop.
(Visual of Greenland melt coverage on June 12th. Image source: NSIDC)
Scientists now are at odds over how fast Greenland melt will increase. Some believe a linear increase in melt is most likely while others believe that exponential increases in Greenland ice sheet melt are not out of the question. Should the increasing pace of melt for Greenland continue, powerful changes in the weather, especially for Europe and North America are in store. This winter and spring’s extreme weather over much of Europe may just be a foretaste of what is to come.
Storms of My Grandchildren on the Horizon
Massive melt from Greenland by or before mid-century means large volumes of fresh water in the North Atlantic. These high volumes of fresh water could substantially slow or even halt the Gulf Stream. Present measures of Gulf Stream circulation already show the current slowing. If these trends continue, the replacement of this warm water stream with cold water from Greenland will radically alter northern hemisphere weather.
The Weather Channel provided a brief summary of some of the possible impacts of slowing Gulf Stream currents here.
Even worse, under human caused climate change, a cooling of the North Atlantic occurs at about the same time tropical and temperate region temperatures begin to rapidly rise. This creates a high gradient between cold air near Greenland and warm air directly to the south. The result, according to models, is powerful storms never seen before in human memory.
In “The Storms of My Grandchildren,” NASA scientist James Hansen warned of the potential for frontal storms large enough to span continents and packing the punch of hurricanes. Is is just these kinds of storms that rapid Greenland melt combined with intensified warming at the tropics could set off.
The conditions for these events appears to be ramping up now and could be present, in the worst case, by as soon as the 2030s. In the meantime, weather conditions are likely to continue to deteriorate as a combination of sea ice melt and Greenland ice sheet melt play havoc with traditional weather patterns.
Alterations to the Northern Hemisphere Jet Stream as demonstrated by the work of Dr. Jennifer Francis is one such change that is already present. And this alteration has already resulted in several instances of enhanced severe weather.
Meanwhile, in more southerly regions, we find that the seasons for tropical storm development are lengthening. Dr. Jeff Masters of WeatherUnderground made the following statement in reference to the early June formation of Tropical Storm Andrea:
Andrea’s formation in June continues a pattern of an unusually large number of early-season Atlantic named storms we’ve seen in recent years. Climatologically, June is the second quietest month of the Atlantic hurricane season, behind November. During the period 1870 – 2012, we averaged one named storm every two years in June, and 0.7 named storms per year during May and June. In the nineteen years since the current active hurricane period began in 1995, there have been fifteen June named storms (if we include 2013′s Tropical Storm Andrea.) June activity has nearly doubled since 1995, and May activity has more than doubled (there were seventeen May storms in the 75-year period 1870 – 1994, compared to 6 in the 19-year period 1995 – 2013.) Some of this difference can be attributed to observation gaps, due to the lack of satellite data before 1966.
So storminess increases at the tropics and storminess increases at the poles. When these two conditions meet, the potential exists for amazingly powerful and freakish storms similar to, but even worse, than Hurricane Sandy. It is the potential of global warming to set in place conditions where powerful storms can combine, persist, and expand over vast areas that is a threat we must consider as Greenland melt continues to increase, Arctic sea ice melt progresses, and warming in the tropics and temperate zones continues to expand.