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IPCC Fourth Assessment Report Working Group 1 report

TitleIPCC Fourth Assessment Report Working Group 1 report
Publication TypeManual Entry
Year of Publication2007
Place PublishedGeneva

The Working Group I contribution to the IPCC Fourth Assessment Report describes progress in understanding of the human and natural drivers of climate change, observed climate change, climate processes and attribution, and estimates of projected future climate change. It builds upon past IPCC assessments and incorporates new findings from the past six years of research. Scientific progress since the Third Assessment Report TAR is based upon large amounts of new and more comprehensive data, more sophisticated analyses of data, improvements in understanding of processes and their simulation in models and more extensive exploration of uncertainty ranges.

Citation Key235


IPCC publications should be considered the foundation for those looking to enhance their knowledge of global climate change and its potential impacts.

Link to section

Section Assesses the projected changes in the tropcial El Nino/La Nina  phenomenon in the CMIP3 climate models.   Note that  the next generation of climate models that are part of CMIP5 are being analyzed and results should be available for the 2013IPCC  Fifth Assessment Report.
"In summary, all models show continued ENSO [El Nino and La Nina] interannual variability in the future no matter what the change in average background conditions, but changes in ENSO interannual variability differ from model to model. Based on various assessments of the current multi-model archive, in which present-day El Niño events are now much better simulated than in the TAR, there is no consistent indication at this time of discernible future changes in ENSO amplitude or frequency."

link to section 8.4.7

Section 8.4.7 assesses the ability of the CMIP3 climate models to simulate the tropical El Nino/La Nina phenomenon.

link to section 3.6.2

section 3.6.2 describes the observations of  El Nino Southern Oscillation (ENSO) phenomenon, and how it has changed in the past. 
" The nature of ENSO has varied considerably over time.", " Thus, whether observed changes in ENSO behaviour are physically linked to global climate change is a research question of great importance."