Global Warming: Scientists 95% Sure
Last week, at the end of my blog I touched on climate change.
It was good timing, because today, the Intergovernmental Panel on Climate Chance released its first report in six years. More than 800 authors and 50 editors from dozens of countries took part in its creation.
So what does it say? In summation, that the effects of climate disruption are accelerating, and that climate scientists are 95 percent certain that human activity caused at least half of climate change in the last half century.
The report is fairly easy to read, as it boxes and highlights its main assertions, prior to explanation. Here are some of the main findings:
*Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased.
*Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850. In the Northern Hemisphere, 1983–2012 was likely the warmest 30-year period of the last 1400 years
*Over the last two decades, the Greenland and Antarctic ice sheets have been losing mass,glaciers have continued to shrink almost worldwide, and Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent.
*The atmospheric concentrations of carbon dioxide (CO2), methane, and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years. CO2 concentrations have increased by 40 percent since pre-industrial times, primarily from fossil fuel emissions and secondarily from net land use change emissions. The ocean has absorbed about 30 percent of the emitted anthropogenic carbon dioxide, causing ocean acidification.
*Human influence on the climate system is clear. This is evident from the increasing greenhouse gas concentrations in the atmosphere, positive radiative forcing, observed warming, and understanding of the climate system.
*Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system. Limiting climate change will require substantial andsustained reductions of greenhouse gas emissions.
*It is very likely that the Arctic sea ice cover will continue to shrink and thin and that Northern Hemisphere spring snow cover will decrease during the 21st century as global mean surface temperature rises. Global glacier volume will further decrease.
Sometimes when we’ll have a really cold snap here in North Dakota when it’s normally warm, or when it will snow very heavily outside of season, it’s not uncommon for me to hear someone say, “Yeah, so much for this global warming crap!”
The thing is, as author Thomas Friedman once pointed out, a person has to look at it more as global “weirding.” A few years ago, Friedman authored a column for the New York Times that really stuck with me. Here are some excerpts:
Of the festivals of nonsense that periodically overtake American politics, surely the silliest is the argument that because Washington is having a particularly snowy winter it proves that climate change is a hoax and, therefore, we need not bother with all this girly-man stuff like renewable energy, solar panels and carbon taxes. Just drill, baby, drill.
Avoid the term “global warming.” I prefer the term “global weirding,” because that is what actually happens as global temperatures rise and the climate changes. The weather gets weird. The hots are expected to get hotter, the wets wetter, the dries drier and the most violent storms more numerous.
The fact that it has snowed like crazy in Washington — while it has rained at the Winter Olympics in Canada, while Australia is having a record 13-year drought — is right in line with what every major study on climate change predicts: The weather will get weird; some areas will get more precipitation than ever; others will become drier than ever.
Historically, we know that the climate has warmed and cooled slowly, going from Ice Ages to warming periods, driven, in part, by changes in the earth’s orbit and hence the amount of sunlight different parts of the earth get. What the current debate is about is whether humans — by emitting so much carbon and thickening the greenhouse-gas blanket around the earth so that it traps more heat — are now rapidly exacerbating nature’s natural warming cycles to a degree that could lead to dangerous disruptions.
With the chaos currently going on in Congress, it’s likely this report isn’t going to get much attention. At least for a while.
Perhaps in another six years when a new report comes out, scientists will be 100 percent sure. Let’s hope, in the meantime, that Mother Nature doesn’t seek revenge on our continued ignorance of manmade global warming.