Changes in global average surface temperature, global average sea level, and northern hemisphere snow cover

Notes from our reviewers

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• Teaching Tips
  For background on this figure, see it in the context of the IPCC AR4 Synthesis Report see [http://www.ipcc.ch/publications_and_data/ar4/syr/en/spms1.html] Figure caption reads: Observed changes in (a) global average surface temperature; (b) global average sea level from tide gauge (blue) and satellite (red) data and (c) Northern Hemisphere snow cover for March-April. All differences are relative to corresponding averages for the period 1961-1990. Smoothed curves represent decadal averaged values, while circles show yearly values. The shaded areas are the uncertainty intervals estimated from a comprehensive analysis of known uncertainties (a and b) and from the time series (c).
• About the Science
  This visualization of several critical data sets is from the IPCC Fourth Assessment (AR4) Synthesis Report from 2007 based on figures and data sources in the Working Group 1 report. Comments from expert scientist: Figure contains important data and is accurate, but page contains no caption, references or other info to help the user.
• About the Pedagogy
  These datasets provide the critical evidence for the primary impacts of the recent rise in atmospheric carbon dioxide concentrations. They will be central to any discussion of climate change. Teacher will need to explain the vertical axis label (difference from 1961-1990) to younger students.
• Technical Details/Ease of Use
  This is a simple and direct visualization of three main climate change datasets with yearly values, decadal averaged values, and uncertainty intervals.