Now we’re supposed to believe much less warming than that is something to fear, is mostly human-caused, and is somehow to be avoided at all costs? Climate science today often seems content to ignore or downplay natural variation that is known to play a big part in Earth’s past, and therefore future.
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Interglacials are, as the name suggests, warm periods between planetary glaciations when the expanse of ice on Earth shrinks, says Phys.org.
Currently, we are in an 11,000 year-long interglacial period known as the Holocene. Prior to this, the Last Interglacial occurred between 115,000 and 130,000 years ago.
During this time, Earth experienced summers that were almost completely ice-free and there was significant vegetation growth in polar regions, changing the ecosystems for life to flourish.
Scientists can look to this Last Interglacial as a potential analog for future global warming.
Indeed, new research, currently under review for publication in the Climate of the Past journal, has turned to the geological record of the Arctic to understand how terrestrial environments responded to the warmer world.
Here, warming was amplified compared to the rest of the northern hemisphere due to ice albedo feedbacks, whereby solar insolation melted ice sheets, reducing the amount of radiation reflected back out to space and causing further warming, creating a positive feedback loop [Talkshop comment – which self-evidently wasn’t permanent].
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The researchers ultimately identified up to 10°C more summer warming in northern Siberia during the Last Interglacial compared to summers today, with fossilized plant material suggesting that mean temperatures of the warmest month could have reached 15°C, while fossil beetles indicate the coldest temperature may have been -38°C. Today, the respective mean temperatures are approximately 3°C and -34°C.
Having said this, in June 2020, the town of Verkhoyansk in Russia measured the highest temperature ever recorded above the Arctic Circle at 38°C, while the lowest temperature recorded is -69°C in Greenland. While these were anomalous, the continued changing climate highlights the need to look to the past to inform the future, when such conditions could become more common.
Dr. Schirrmeister notes that while the Last Interglacial warming mostly impacted summer temperatures, future climate change is expected to more broadly impact winter months due to anthropogenic activity.
Nevertheless, ice sheet retreat, loss of sea ice and melting permafrost are all observed in the Arctic today, highlighting the importance of continued research into the sensitivity of Earth to rising temperatures during the Last Interglacial.
Full article here.
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Image credit: grida.no / NOAA
via Tallbloke’s Talkshop
December 19, 2024 at 09:57AM
Iowa Climate Science Education 