“…there is now strong evidence linking specific [extreme] events or an increase in their numbers to the human influence on climate.” — Coumou and Rahmstorf 2012.
“We are confronted with the fierce urgency of now. …We may cry out desperately for time to pause in her passage, but time is deaf to every plea and rushes on. Over the bleached bones and jumbled residues of numerous civilizations are written the pathetic words, ‘Too late.'” — Dr. Martin Luther King, Jr. [emphasis added]
2016 is on track to be a record-hot year for the history books. Accumulations of heat-trapping gasses in the range of 402 ppm CO2 and 490 ppm CO2e have pushed the global temperature trend into an inexorable upward rise. Meanwhile, increasingly severe climate change-related events ranging from mass coral bleaching, to glacial and sea ice melt, to tree death, to ocean health decline, to the expanding ranges of tropical infectious diseases, to worsening extreme weather events have occurred the world over. This global temperature spike and related ramp-up of extreme events continued throughout a year that is setting up to follow 2014 and 2015 as the third record-hot year in a row.
(2015 saw a substantial jump in global temperatures. 2016 is also on track to hit new record highs. The above graph, by Gavin Schmidt of NASA GISS, provides a vivid illustration of an inexorable warming trend with 2016 as the hottest year yet. According to Gavin, a strong new record for 2016 appears to be a lock. Image source: Climate of Gavin.)
Now, after NASA’s report showing that September 2016 was 1.13 C hotter than 1880s averages (or 0.91 C hotter than NASA’s 20th-century baseline measure), this year is setting up to be the warmest ever recorded by a wide margin. Overall, the first nine months of 2016 have averaged 1.25 C above 1880s temperatures. Meanwhile, the climate year — which runs from December through November — is tracking 1.26 C above 1880s temperatures during the ten-month period of December to September.
2016 as much as 1.25 C Hotter than 1880s Averages
As a result, it appears likely that 2016 will see temperatures in the range of 1.19 C to 1.25 C hotter than 1880s averages. That’s about 0.1 C hotter than 2015 — which is pretty significant considering the fact that the average rate of decadal warming (the rounded rate of global warming every 10 years) has been in the range of 0.15 C since the late 1970s. This year’s temperatures now appear set to exceed 1998’s values by around 0.35 C — or about one-third of the entire warming total seen since large-scale human greenhouse gas emissions began during the late 19th century. This excession should permanently put to rest previous widely circulated false notions that global warming somehow stopped following the strong El Nino year of 1998.
Many responsible sources are now warning that current temperatures are uncomfortably close to two major climate thresholds — 1.5 C global warming and 2.0 C global warming. At the current rate of warming, we appear set to exceed the 1.5 C mark in the annual measure in just one to two decades. Hitting 2 C by or before mid-century has become a very real possibility. Scientists have been urging the global community to avoid 2 C warming before 2100 (and 1.5 C if at all possible), but the current path brings us to that level of warming in just over 30-50 years, not over the 84 years remaining in this century. And just maintaining current rates of warming without significant added feedbacks from the Earth System would result in Earth hitting close to 3 C warming by 2100 — a level that would inflict severe harm to life on Earth, including human civilizations.
(According to NASA, September 2016 edged out September 2014 as the hottest September in the 136-year climate record. This occurred while the Equatorial Pacific was flipped into a cool phase, which tends to lower global temperatures. Despite this natural variability-related switch pulling global temperatures down, NASA shows a globe in which few regions experienced below-average temperatures and where the highest concentration of record-warm temperatures are centered near the northern polar region. This display of counter-trend warming and strong polar amplification are both signature effects of human-caused climate change. Image source: NASA GISS.)
Focusing back on 2016, it appears the La Nina that struggled throughout August and early September is again making a decent attempt to form, at least as a weak event. This should tend to pull October, November and December temperatures into the 1 to 1.1 C above 1880s departure range. As a result, final averages for 2016 should be slightly lower than averages for the period running from December to September. But, as noted above, we are still on track to see a very significant jump above the 2015 end atmospheric temperature totals.
Climate Impacts from Added Global Heat Continue to Worsen
All this extra heat in the system will work to worsen the already extreme climate and weather events we are seeing. Potentials for droughts, floods, heatwaves and wildfires will increase. High atmospheric moisture loading will continue to pump up peak storm potentials when storms do form. Added heat will tend to accumulate at the poles more than in the tropics or middle latitudes. As a result, upper-level wind patterns will likely continue to see more anomalous features along a worsening trend line. Ice in all forms will see stronger heat forcings overall, adding risk that both land and sea ice melt rates will increase.
(In the mid-2010s, Earth entered a temperature range averaging 1 C above pre-industrial levels. Such temperatures begin to threaten key climate impacts like permafrost thaw, 3-4 meters of sea-level rise from West Antarctic Ice Sheet melt, risk of up to 80 percent mountain glacier loss, complete Arctic sea ice loss during summer, and 6-7 meters of sea level rise from Greenland melt. In the near 1 C range, risks of these impacts, though a possibility, remain somewhat lower. But as temperatures approach 1.5 and 2 C above pre-industrial levels, risks rise even as West Antarctic glacial melt and polar ocean acidification start to become serious factors. Image source: Solving the Climate Stalemate.)
At 1 to 1.3 C above 1880s levels, we should see a quickening in the rate of sea-level rise. How much is uncertain. However, this temperature range is very close to peak Eemian Stage levels when oceans were around 15 to 25 feet higher than they are today. The current rapid rate of temperature change will also continue to have worsening impacts on creatures who are adapted to inhabit specific climate zones. The rapid rise in global temperatures is forcing an equally rapid movement of climate zones toward the poles and up mountains. This affects pretty much all life on Earth and unfortunately some species will be hard-pressed to handle the insult as certain habitats basically move off-planet. This impact is particularly true for corals, trees and other species that are unable to match the rapid pace of climate zone motion. We have already seen very severe impacts in the form of mass coral and tree death the world over. Warming in the 1 to 1.3 C range also provides an increasing ocean stratification pressure — one that has already been observed to increase the prevalence of ocean dead zones and one that will tend to shrink overall ocean vitality and productivity.
Fierce Urgency For Climate Action
Despite all these negative impacts, we are still currently outside the boundary of the worst potential results of climate change. Stresses are on the rise from various related factors, but these stresses have probably not yet reached a point of no return for human civilization and many of the reefs, forests, and living creatures we have grown to cherish. Rapid mitigation through a swift transition away from fossil fuels is still possible. Such a response now has a high likelihood of successfully protecting numerous civilizations while saving plant and animal species across the planet. That said, at this point, some damage is, sadly, unavoidable. But the simple fact that we are now starting to face the harmful consequences of a century and a half of fossil fuel burning is no excuse for inaction. To the contrary, the beginning of these harms should serve as a clarion call for our redoubled efforts.
Hat tip to Kevin Jones
Hat tip to Florifulgurator