Sensitivity of carbon budgets to permafrost carbon feedbacks and non-CO2 forcings

  title={Sensitivity of carbon budgets to permafrost carbon feedbacks and non-CO2 forcings},
  author={Andrew H. MacDougall and Kirsten Zickfeld and Reto Knutti and H. Damon Matthews},
  journal={Environmental Research Letters},
The near proportionality between cumulative CO2 emissions and change in near surface temperature can be used to define a carbon budget: a finite quantity of carbon that can be burned associated with a chosen ‘safe’ temperature change threshold. Here we evaluate the sensitivity of this carbon budget to permafrost carbon dynamics and changes in non-CO2 forcings. The carbon budget for 2.0 ◦ C ?> of warming is reduced from 1320 Pg C when considering only forcing from CO2 to 810 Pg C when… 

Figures and Tables from this paper

The influence of non-CO2 forcings on cumulative carbon emissions budgets

Carbon budgets provide a useful tool for policymakers to help meet the global climate targets, as they specify total allowable carbon emissions consistent with limiting warming to a given temperature

The impact of Earth system feedbacks on carbon budgets and climate response

  • J. LoweD. Bernie
  • Environmental Science
    Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
  • 2018
Initial estimates are made to show that the combined impact from typically unrepresented Earth system processes may be important for the achievability of limiting warming to 1.5°C or 2°C above pre-industrial levels.

Path-dependent reductions in CO2 emission budgets caused by permafrost carbon release

Emission budgets are defined as the cumulative amount of anthropogenic CO2 emission compatible with a global temperature-change target. The simplicity of the concept has made it attractive to

Uncertainty in carbon budget estimates due to internal climate variability

Remaining carbon budget specifies the cap on global cumulative CO2 emissions from the present-day onwards that would be in line with limiting global warming to a specific maximum level. In the

Estimating Carbon Budgets for Ambitious Climate Targets

Carbon budgets, which define the total allowable CO2 emissions associated with a given global climate target, are a useful way of framing the climate mitigation challenge. In this paper, we review

Timescales of the permafrost carbon cycle and legacy effects of temperature overshoot scenarios

It is shown that feedbacks between water-, energy- and carbon cycles allow for multiple steady-states in permafrost regions, which differ with respect to the physical state of the soil, the soil carbon concentrations and the terrestrial carbon uptake and -release.

Path Independence of Carbon Budgets When Meeting a Stringent Global Mean Temperature Target After an Overshoot

Emission pathways that are consistent with meeting the Paris Agreement goal of holding global mean temperature rise well below 2 °C often assume a temperature overshoot. In such overshoot scenarios,

The Role of Remaining Carbon Budgets and Net-Zero CO2 Targets in Climate Mitigation Policy

Here, we review recent estimates of the remaining carbon budget, with a focus on characterizing key uncertainties and assessing the implications for net-zero CO2 targets and climate policy. Recent

Permafrost and Climate Change: Carbon Cycle Feedbacks From the Warming Arctic

Rapid Arctic environmental change affects the entire Earth system as thawing permafrost ecosystems release greenhouse gases to the atmosphere. Understanding how much permafrost carbon will be

Cumulative carbon emissions budgets consistent with 1.5 °C global warming

The Paris Agreement1 commits ratifying parties to pursue efforts to limit the global temperature increase to 1.5 °C relative to pre-industrial levels. Carbon budgets2–5 consistent with remaining



The proportionality of global warming to cumulative carbon emissions

It is shown that the carbon–climate response (CCR), defined as the ratio of temperature change to cumulative carbon emissions, is approximately independent of both the atmospheric CO2 concentration and its rate of change on these timescales.

Quantifying Carbon Cycle Feedbacks

Abstract Perturbations to the carbon cycle could constitute large feedbacks on future changes in atmospheric CO2 concentration and climate. This paper demonstrates how carbon cycle feedback can be

Constraining the Ratio of Global Warming to Cumulative CO2 Emissions Using CMIP5 Simulations

AbstractThe ratio of warming to cumulative emissions of carbon dioxide has been shown to be approximately independent of time and emissions scenarios and directly relates emissions to temperature. It

Vulnerability of Permafrost Carbon to Climate Change: Implications for the Global Carbon Cycle

ABSTRACT Thawing permafrost and the resulting microbial decomposition of previously frozen organic carbon (C) is one of the most significant potential feedbacks from terrestrial ecosystems to the

The origin and limits of the near proportionality between climate warming and cumulative CO2 emissions.

AbstractThe transient climate response to cumulative CO2 emissions (TCRE) is a useful metric of climate warming that directly relates the cause of climate change (cumulative carbon emissions) to the

Warming caused by cumulative carbon emissions towards the trillionth tonne

It is found that the peak warming caused by a given cumulative carbon dioxide emission is better constrained than the warming response to a stabilization scenario, and policy targets based on limiting cumulative emissions of carbon dioxide are likely to be more robust to scientific uncertainty than emission-rate or concentration targets.

If Anthropogenic CO2 Emissions Cease, Will Atmospheric CO2 Concentration Continue to Increase?

AbstractIf anthropogenic CO2 emissions were to suddenly cease, the evolution of the atmospheric CO2 concentration would depend on the magnitude and sign of natural carbon sources and sinks.

Climate change and the permafrost carbon feedback

It is found that current evidence suggests a gradual and prolonged release of greenhouse gas emissions in a warming climate and a research strategy with which to target poorly understood aspects of permafrost carbon dynamics is presented.

Path independence of climate and carbon cycle response over a broad range of cumulative carbon emissions

Abstract. Recent studies have identified an approximately proportional relationship between global warming and cumulative carbon emissions, yet the robustness of this relationship has not been tested

Setting cumulative emissions targets to reduce the risk of dangerous climate change

An inverse approach to coupled climate-carbon cycle modeling is presented, which allows the probability that any given level of carbon dioxide (CO2) emissions will exceed specified long-term global mean temperature targets for “dangerous anthropogenic interference,” taking into consideration uncertainties in climate sensitivity and the carbon cycle response to climate change.