Siberian permafrost thaw warning sparked by cave data

BBC, February 22

Evidence from Siberian caves suggests that a global temperature rise of 1.5C could see permafrost thaw over a large area of Siberia.

A study shows that more than a trillion tonnes of the greenhouse gases CO2 and methane could be released into the atmosphere as a result.

An international team has published details in the journal Science.

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  • Preventing climate change: The size of the energy challenge

    Eurekalert, Jan 7

    Washington, DC — In 2004 a very popular study aimed to address climate change by deploying wedges of different existing energy technologies or approaches. According to the study by Robert Socolow and Stephen Pacala, each wedge would avoid one billion tons of carbon (1 GtC) emissions per year after 50 years. The study showed that, at that time, seven wedges could stabilize carbon dioxide emissions relative to what would happen if things remained “business-as-usual.”

    A new perspective paper from a group including Carnegie’s Ken Caldeira uses the wedge approach to estimate the size of the energy challenge posed by climate change today. It is published January 9 by Environmental Research Letters.

    The perspective’s authors showed that as a result of increased emissions, merely achieving what was considered “business-as-usual” in 2004 would require the development and deployment of 12 wedges. Stabilizing emissions at current levels would require another 9 wedges. Decreasing emissions to the level needed to prevent climate change would need an additional 10 wedges. Altogether, 31 wedges would be required to stabilize the Earth’s climate.

    “To solve the climate problem while providing the energy needed for modern industrial society, new energy technologies must be developed and deployed at an enormous and increasing rate,” Caldeira said.

    Amount and timing of permafrost carbon release in response to climate warming

    Tellus, February 15, 2011

    The thaw and release of carbon currently frozen in permafrost will increase atmospheric CO2 concentrations and amplify surface warming to initiate a positive permafrost carbon feedback (PCF) on climate. We use surface weather from three global climate models based on the moderate warming, A1B Intergovernmental Panel on Climate Change emissions scenario and the SiBCASA land surface model to estimate the strength and timing of the PCF and associated uncertainty. By 2200, we predict a 29–59% decrease in permafrost area and a 53–97 cm increase in active layer thickness. By 2200, the PCF strength in terms of cumulative permafrost carbon flux to the atmosphere is 190 ± 64 Gt C. This estimate may be low because it does not account for amplified surface warming due to the PCF itself and excludes some discontinuous permafrost regions where SiBCASA did not simulate permafrost. We predict that the PCF will change the arctic from a carbon sink to a source after the mid-2020s and is strong enough to cancel 42–88% of the total global land sink. The thaw and decay of permafrost carbon is irreversible and accounting for the PCF will require larger reductions in fossil fuel emissions to reach a target atmospheric CO2 concentration.

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