Sightings from the Treehouse: Elements of Climate Change - Ice and Permafrost Loss
Sightings from the Treehouse is an investigative blog series on climate change and the environment, from GIPL’s Power Wise Director, Bob Donaghue. You can read the first, second, and third blogs here.
The most significant impacts of global warming are found in the polar regions, since temperatures are twice as high there compared to the global average temperature. Increasing ice and permafrost melt threaten our globe in a variety of ways. I hope you will read the previous blog on rising temperatures since it forms the basis of our further exploration. It is quite simple: temperatures increase, ice melts and sea levels rise. The evidence is clear that global temperatures are rising and new records seem to be set each year. What is that doing in our polar areas, the earth’s natural air conditioner?Ice MeltGlobal temperatures have increased about 1.9 degrees F since pre-industrial times, but have doubled in the Arctic during the same period due to a phenomenon called Arctic amplification. In 2016, Arctic temperatures were 6.3 degrees F above 1900s levels. This increased heating due to amplification is leading to tremendous loss of Arctic ice, both glacial and sea ice. This is particularly evident during the summer. The rate of Arctic ice melt is about 13% per decade. The albedo effect is when white ice reflects the sun’s heat back into the atmosphere serving to cool the planet, but as ocean ice melts, the dark open water absorbs the sun’s heat and adds to the increased temperatures and thus sea level rise – a positive feedback. Note that “positive” does not mean good but that it simply amplifies rather than dampens (negative feedback) the force of the change. In this case, and with permafrost below, this is bad and could be catastrophic.According to a 2017 NOAA assessment, sea level rise from 1880 through today is about 8-9 inches with 3 inches occurring since 1993. They estimate the range in sea level rise from glacial melt and ocean heating to be from 1 to 8 feet by 2100 depending on the success of emission reductions. Based on evolving evidence of ice melt in Antarctica, the higher levels and beyond are very plausible. NOAA cites that up to 6 million people in the US will be displaced at about 6 feet sea level rise. Permafrost LossAnother concerning result of the rapidly warming Arctic is the thawing of historically frozen rock and soil called permafrost. Soil is much more than finely ground rock, containing significant amounts of organic matter that slowly decomposes (rots). Methane is a gas that comes from this decomposition and is the major ingredient in the natural gas we burn in our homes and businesses. When released to the atmosphere unburnt, it is a much more powerful greenhouse gas than carbon dioxide, 21 to 27 times as powerful depending on the source. When thawed, this methane gas bubbles to the surface and is released into the air adding to the heat trapping ability of the atmosphere - another potentially dangerous positive feedback loop. As the Arctic warms, it thaws more permafrost on the land and methane hydrates from the ocean floor, releasing additional methane that traps more heat in the atmosphere causing temperatures to rise even further.

