Guest essay by Eric Worrall

Climate scientists are worried a beaver boom may be helping to melt the Arctic ice.

Beavers gnawing away at the Arctic permafrost

by  Alfred Wegener Institute
JUNE 30, 2020

Alaska’s beavers are profiting from climate change, and spreading rapidly. In just a few years’ time, they have not only expanded into many tundra regions where they’d never been seen before; they’re also building more and more dams in their new homes, creating a host of new water bodies. This could accelerate the thawing of the permafrost soils, and therefore intensify climate change, as an International American-German research team reports in the journal Environmental Research Letters.

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This has already affected the water balance. Apparently, the rodents intentionally do their work in those parts of the landscape that they can most easily flood. To do so, sometimes they dam up small streams, and sometimes the outlets of existing lakes, which expand as a result. “But they especially prefer drained lake basins,” Benjamin Jones, lead author of the study, and Nitze report. In many cases, the bottoms of these former lakes are prime locations for beaver activity. “The animals have intuitively found that damming the outlet drainage channels at the sites of former lakes is an efficient way to create habitat. So a new lake is formed which degrades ice-rich permafrost in the basin, adding to the effect of increasing the depth of the engineered waterbody,” added Jones. These actions have their consequences: in the course of the 17-year timeframe studied, the overall water area in the Kotzebue region grew by 8.3 percent. And roughly two-thirds of that growth was due to the beavers.

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Read more: https://phys.org/news/2020-06-beavers-gnawing-arctic-permafrost.html

The abstract of the study;

Increase in beaver dams controls surface water and thermokarst dynamics in an Arctic tundra region, Baldwin Peninsula, northwestern Alaska

Benjamin M Jones^1,6, Ken D Tape², Jason A Clark², Ingmar Nitze³, Guido Grosse^3,4and Jeff Disbrow⁵

Published 30 June 2020 • © 2020 The Author(s). Published by IOP Publishing Ltd

Beavers are starting to colonize low arctic tundra regions in Alaska and Canada, which has implications for surface water changes and ice-rich permafrost degradation. In this study, we assessed the spatial and temporal dynamics of beaver dam building in relation to surface water dynamics and thermokarst landforms using sub-meter resolution satellite imagery acquired between 2002 and 2019 for two tundra areas in northwestern Alaska. In a 100 km² study area near Kotzebue, the number of dams increased markedly from 2 to 98 between 2002 and 2019. In a 430 km² study area encompassing the entire northern Baldwin Peninsula, the number of dams increased from 94 to 409 between 2010 and 2019, indicating a regional trend. Correlating data on beaver dam numbers with surface water area mapped for 12 individual years between 2002 and 2019 for the Kotzebue study area showed a significant positive correlation (R² = 0.61; p < .003). Beaver-influenced waterbodies accounted for two-thirds of the 8.3% increase in total surface water area in the Kotzebue study area during the 17 year period. Beavers specifically targeted thermokarst landforms in their dam building activities. Flooding of drained thermokarst lake basins accounted for 68% of beaver-influenced surface water increases, damming of lake outlets accounted for 26%, and damming of beaded streams accounted for 6%. Surface water increases resulting from beaver dam building likely exacerbated permafrost degradation in the region, but dam failure also factored into the drainage of several thermokarst lakes in the northern Baldwin Peninsula study region, which could promote local permafrost aggradation in freshly exposed lake sediments. Our findings highlight that beaver-driven ecosystem engineering must be carefully considered when accounting for changes occurring in some permafrost regions, and in particular, regional surface water dynamics in low Arctic and Boreal landscapes.

Read more: https://iopscience.iop.org/article/10.1088/1748-9326/ab80f1

Let us hope scientists find a way to mitigate the damage done by the exploding beaver population before it is too late.

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Guest essays by Eric Worrall

Imagine the horror of being able to swim at Blackpool beach without needing a resuscitation team with a hypothermia kit on standby.

Climate change: 40°C summer temperatures could be common in UK by 2100

July 1, 2020 1.46am AEST
Lisa Baldini
Lecturer in Environmental Science, Teesside University

A stark warning about the kind of summer that could become routine in the UK by the end of this century has been issued in a new study by the country’s Met Office.

Using temperature data and climate model simulations, the researchers tested the likelihood of UK temperatures exceeding 30°C, 35°C, and 40°C each summer over the next 80 years.

They found that if global greenhouse gas emissions continue to rise, temperatures exceeding 40°C could be reached somewhere in the UK every three-and-a-half years by 2100.

If you live or have travelled in a hot climate, you might know the stifling heat that envelops your body when the thermometer breaks 40°C. But there is a difference between experiencing that kind of heat from a pool or through the window of an air conditioned hotel room, and living in that heat for several days without reprieve. 

In England alone, 2,000 people every year already die from heat related illnesses. While traditionally warmer climes have adapted over time to soaring summer temperatures, the UK is not prepared to handle these kinds of heatwaves.

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The highest temperature ever recorded in the UK was broken on July 25 2019, when the mercury hit 38.7°C in Cambridge. That same summer, temperatures in France soared to 46°C and claimed 1,500 lives. Although devastating, this was nothing compared to the 15,000 victims who succumbed during France’s August 2003 heatwave.

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Read more: https://theconversation.com/climate-change-40-c-summer-temperatures-could-be-common-in-uk-by-2100-141479

The MET study is available here.

According to The Conversation author Lisa Baldini, the UK is not prepared to handle these kinds of heatwaves.

But even if global warming occurs as predicted, its not like 40C British heatwaves will become a common occurrence starting tomorrow. We’re talking about a gradual change. By the end of 80 years of slowly rising temperatures (or falling temperatures or whatever) UK people would be well and truly adapted to whatever climate they experience by the end of the century, just as British colonists in Australia quickly adapted to our much warmer climate.

The death of 1500 people in the 2019 heatwave, or the 15,000 who died in 2003, is a tragedy. But according to the UK Government, there were 49,410 excess deaths in the winter of 2017-18, and 23,200 deaths in the 2018-19 winter. Milder winters would likely reduce overall excess mortality. A few heatwaves seems a small price to pay, to reduce that dreadful winter excess mortality rate.

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