The Ocean and Cryosphere in a Changing Climate

This IPCC Special Report provides the latest comprehensive assessment of the ocean and cryosphere in a changing climate. It serves policymakers, decision makers, stakeholders, and all interested parties with unbiased, up-to-date, policy-relevant information. This title is also available as Open Access on Cambridge Core

Report of the the IPCC Expert Meeting on Emission Estimation of Aerosols Relevant to Climate Change

This report is supporting material prepared for consideration by the IPCC. It was reviewed by participants of the Geneva meeting, but not reviewed through the IPCC formal process

IPCC Expert Meeting Report

This report summarizes the findings and recommendations from the Expert Meeting on New Scenarios, which focuses on the policymaking perspective of climate change, and on climate modeling scenarios for near term and long term

IPCC Expert Meeting on The Science to Address UNFCCC Article 2 including Key Vulnerabilities

This report contains supporting material to examine the science relating to stabilizing greenhouse gas concentrations at a level that would prevent dangerous anthropogenic interference. The report was prepared for consideration by the IPCC, but it has not been subjected to formal IPCC review processes

Further Work of the IPCC on Emission Scenarios

This report summarizes recommendations for the development and assessment of new emission scenarios for possible use in the IPCC 5th Assessment Report

Uncertainty and climate change policy

The paper consists of a summary of the main sources of uncertainty about climate change, and a discussion of the major implications for economic analysis and the formulation of climate policy. Uncertainty typically implies that the optimal policy is more risk-averse than otherwise, and therefore enhances the case for action to mitigate climate change

Counteracting the climate effects of volcanic eruptions using short-lived greenhouse gases

A large volcanic eruption might constitute a climate emergency, significantly altering global temperature and precipitation for several years. Major future eruptions will occur, but their size or timing cannot be predicted. We show, for the first time, that it may be possible to counteract these climate effects through deliberate emissions of short-lived greenhouse gases, dampening the abrupt impact of an eruption. We estimate an emission pathway countering a hypothetical eruption 3 times the size of Mount Pinatubo in 1991. We use a global climate model to evaluate global and regional responses to the eruption, with and without counteremissions. We then raise practical, financial, and ethical questions related to such a strategy. Unlike the more commonly discussed geoengineering to mitigate warming from long-lived greenhouse gases, designed emissions to counter temporary cooling would not have the disadvantage of needing to be sustained over long periods. Nevertheless, implementation would still face significant challenges

Implications of "peak oil" for atmospheric CO2 and climate

Unconstrained CO2 emission from fossil fuel burning has been the dominant cause of observed anthropogenic global warming. The amounts of "proven" and potential fossil fuel reserves are uncertain and debated. Regardless of the true values, society has flexibility in the degree to which it chooses to exploit these reserves, especially unconventional fossil fuels and those located in extreme or pristine environments. If conventional oil production peaks within the next few decades, it may have a large effect on future atmospheric CO2 and climate change, depending upon subsequent energy choices. Assuming that proven oil and gas reserves do not greatly exceed estimates of the Energy Information Administration, and recent trends are toward lower estimates, we show that it is feasible to keep atmospheric CO2 from exceeding about 450 ppm by 2100, provided that emissions from coal, unconventional fossil fuels, and land use are constrained. Coal-fired power plants without sequestration must be phased out before mid-century to achieve this CO2 limit. It is also important to "stretch" conventional oil reserves via energy conservation and efficiency, thus averting strong pressures to extract liquid fuels from coal or unconventional fossil fuels while clean technologies are being developed for the era "beyond fossil fuels". We argue that a rising price on carbon emissions is needed to discourage conversion of the vast fossil resources into usable reserves, and to keep CO2 beneath the 450 ppm ceiling.Comment: (22 pages, 7 figures; final version accepted by Global Biogeochemical Cycles

A Method for Enhancing Capacity of Local Governance for Climate Change Adaptation

UID/AMB/04085/2019The lack of capacity for climate change adaptation at the subnational level has been highlighted as a key barrier to implementing the UNFCCC National Adaptation Plans. At the same time, the adaptive capacity of local governance is highly context sensitive, making a “one-size fits all” approach inappropriate. Thus, a versatile methodological approach for application in various local contexts is required. There are several indicator-based local governance assessment methods for evaluating the effectiveness of local governance for climate change adaptation. However, they fall short of identifying and prioritizing between key factors within local governance for enhancing adaptive capacity and driving positive change. Building on adaptation theory, the authors propose combining two methodological approaches, the Capital Approach Framework for evaluating the adaptive capacity of local governance and Fuzzy Cognitive Mapping for identifying leverage points, into one integrated modeling approach, which can be applied by local researchers. This paper describes the process and benefits of combining the methodological approaches, with an example provided as supporting information. Assisting decision-makers and policy planners from subnational governance in identifying leverage points to focus and maximize impact of capacity-enhancing measures would make a key contribution for successful implementation of the UNFCCC National Adaptation Plans.publishersversionpublishe