Target practice: where should we aim to prevent dangerous climate change?
In The Big Melt Carbon Equity assessed the recent climate science. This effort was prompted by the significant reduction in Arctic sea ice during the last northern summer.
The science review begged the question of whether the greenhouse gas reduction goals being adopted by governments and other interested parties are still adequate. To address this issue in detail David Spratt and Philip Sutton have compiled Target Practice.
A third paper, Rising to the Challenge, is in preparation. It will look at how we might go about achieving the goals set out in Target Practice.
Summary
• Policies have not been constructed within a framework of fully solving the problem.
• Actions proposed should be doubly-practical: they should deliver tangible results in the real world and crucially they must also fully solve the problem
• We suggest the goal is a climate safe for all people and all species over ‘all’ generations
* The loss of the Arctic sea ice, in all likelihood at an increase of less than 1ºC in global average temperature unambiguously represents dangerous human interference with the climate and therefore global temperatures should not have exceeded the levels three decades ago when Arctic sea-ice disintegration commenced in order to avoid dangerous climate change.
• The widely-promoted 2ºC target cap is not credible, initiating climate feedbacks on earth and in the oceans, on ice-sheets and on the tundra, taking the earth past significant tipping points.
• Proposals for a 60% cut on 1990 levels by 2050 in the developed world implies a 3ºC target. The last time temperatures were 3°C higher than our pre-industrial levels, the northern hemisphere was free of glaciers and ice sheets, beech trees grew in the Transantarctic mountains, sea levels were 25 metres higher.
• In order to avoid the loss of the Arctic icesheet, a safe target would be 0.5ºC. We therefore propose that a safe-climate temperature increase cap be 0.5ºC and greenhouse gas level of 320 ppm CO2e, a level to which we should aim to return the planet if we value biodiversity and human life. There is no ideal achievement timetable other than as fast as possible.
• To return to the safe zone we need to bring the global temperature and the atmospheric greenhouse gases down from their present levels; and
• This means that no further greenhouse gases should be added to the air and there needs to be a very significant decay in the level of the short-residence-period greenhouse gases and other positive forcing (warming) agents in the atmosphere (e.g. soot) and a major draw down of CO2 using natural carbon sinks and deliberate human capture and sequestration.
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