Overview Studies - IPCC

IPCC AR6 Impacts Summary 0222 - PDF, 35 pages

IPCC AR6 Science Summary 0821 - PDF, 42 pages

How do we know humans are causing climate change?

Humans produce large amounts of greenhouse gas emissions, primarily through fossil fuel burning, agriculture,deforestation and decomposing waste.

-IPCC Sixth Assessment Report

2018: IPCC on 1.5°C vs 2°C and 12 Years to Go, 1018 Exec Summary - PDF, 34 pages

2014: IPCC 5 Synthesis Report 1114 - PDF, 116 pp

2014: IPCC 5 Impacts Summary - PDF, 44 pp

IPCC 5 Crop Impacts - PDF, 82 pp

Bars showing % of the 56 or more studies considered that found various % yield changes (color key at right). The black horizontal bars show the line between yields higher than now and lower ones. Farther into the future, more and more studies project lower yields, especially much lower yields. Assumptions about adaptation, CO2 fertilization and other matters varied from study to study.

2014: IPCC 5 Mitigation Summary - PDF, 33 pp

2013: IPCC 5th Science Assessment - Technical Summary - PDF, 84 pp

Forecast Changes as Fraction of Global Mean Change

CMIP3 models are vintage ~2004, while CMIP5 models are vintage ~2011. Relative temperature changes on 97% of land exceed mean global temperature changes (red, dark red & purple), especially in the Arctic, while relative changes over 92% of the oceans (not the Arctic) are less than mean global temperature change (orange & light orange). Temperatures change more toward the poles.

These are relative to the global mean. For absolute projections of temperature change,see the maps from the 2014 Impacts summary, a bit above the 2013 Science Assessment.

That is, land surfaces warm faster than ocean surfaces.
Precipitation changes, however, are location-specific % changes relative to now. Increases will be strongest in the Arctic, while decreases will be greatest around the Mediterranean.