Runaway carbon dynamics - The Global Warming Accelerators

What is Runaway Carbon Dynamics?

Runaway carbon dynamics is the rapid increases in carbon dioxide concentrations in the atmosphere due to positive feedbacks. Runaway carbon dynamics would lead to an acceleration in global warming. It includes the likely reversal of the land based carbon sinks in plants and soil, which today absorb carbon from the atmosphere, especially due to increasing plant growth caused by the fertilising effect of higher concentrations of carbon dioxide in the atmosphere.

The role of the oceans in taking up carbon is complex. With warmer water dissolving less CO2, warmer surface water tends to make for less overturning and thus less downwards transport of CO2. However, stronger winds especially in the Southern Ocean may bring to the surface colder water that has higher CO2 concentrations due to biochemistry, and which then outgases.

Other contributors to an acceleration in global warming include more frequent forest fires, the thawing of permafrost (which allows the decay of peat stored in the Arctic tundra), and the release of methane stored in ice-like hydrate crystals on the ocean floor.

These effects add up to a more rapid increase in greenhouse gas concentration in the atmosphere, adding to the enhanced greenhouse effect, accelerating global warming and leading to a greater and more rapid onset of all climate impacts. Exactly how rapid this process will be, and how far it will go is not yet understood, but once it gets under way it may be difficult to stop. Such an acceleration of global warming is equivalent to a greater climate sensitivity, and means that to stabilise greenhouse gas concentrations and global warming at any particular ‘safe’ level will require greater reductions in greenhouse gas emissions.