Assessing the UNIPCC fifth assessment report

The first part of the UNIPCC AR5 is due to be published in the coming days. At the Conversation, Research Fellows Roger Jones and Celeste Young at Victoria University have posted Explainer: how to read an IPCC report. It contains some useful stuff on penetrating the coded language of the IPCC report. You will be better able to decode what the IPCC mean by various levels of confidence. However, the authors are very careful not to give people a free rein in thinking for themselves. Therefore they stress that the language is complex, and any questions need to be answered by an expert. After all, it would not do to have people misinterpreting the science.

I suggest an alternative method of understanding the science. That is comparing what is said now with what the consensus said back in 2007 in AR4. The AR4 is available at the United Nations Intergovernmental Panel on Climate Change website at the following location.

http://www.ipcc.ch/publications_and_data/publications_ipcc_fourth_assessment_report_synthesis_report.htm

Figure 2.4 Radiative forcing components of SYR.

It would be nice to see the comparative estimates, particularly on whether aerosols have a comparatively large negative role and whether natural factors are still less than 10% of the net total.

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Figure 2.4. Global average radiative forcing (RF) in 2005 (best estimates and 5 to 95% uncertainty ranges) with respect to 1750 for CO2, CH4, N2O and other important agents and mechanisms, together with the typical geographical extent (spatial scale) of the forcing and the assessed level of scientific understanding (LOSU). Aerosols from explosive volcanic eruptions contribute an additional episodic cooling term for a few years following an eruption. The range for linear contrails does not include other possible effects of aviation on cloudiness. {WGI Figure SPM.2}

Figure SPM.6. Projected surface temperature changes for the late 21st century (2090-2099).

An updated map on a comparable basis would be useful, especially for the most concerning area of the Arctic.


Figure SPM.6. Projected surface temperature changes for the late 21st century (2090-2099). The map shows the multi-AOGCM average projection for the A1B SRES scenario. Temperatures are relative to the period 1980-1999. {Figure 3.2}

Table SPM.2. Examples of some projected regional impacts.


It would be nice to have an update on how the short term impacts are doing. These all had high confidence or very high confidence

In Africa

By 2020, between 75 and 250 million of people are projected to be exposed to increased water stress due to climate change.

By 2020, in some countries, yields from rain-fed agriculture could be reduced by up to 50%. Agricultural production, including access to food, in many African countries is projected to be severely compromised. This would further adversely affect food security and exacerbate malnutrition.

In Australia and New Zealand

By 2020, significant loss of biodiversity is projected to occur in some ecologically rich sites, including the Great Barrier Reef and Queensland Wet Tropics.

Small Islands

Sea level rise is expected to exacerbate inundation, storm surge, erosion and other coastal hazards, thus threatening vital infrastructure, settlements and facilities that support the livelihood of island communities.

Please note the graphs used are available at this website and are IPCC Copyright.


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