laws and policies
1990
1st Assessment report IPCC
The IPCC first assessment report was completed in 1990 and was published in three volumes, each with a Summary for Policymakers
The executive summary of the Working Group I report includes:
- We are certain of the following: there is a natural greenhouse effect...; emissions resulting from human activities are substantially increasing the atmospheric concentrations of the greenhouse gases;
- We calculate with confidence that: ...CO2 has been responsible for over half the enhanced greenhouse effect;
- Based on current models, we predict: under [BAU] increase of global mean temperature during the [21st] century of about 0.3 oC per decade (with an uncertainty range of 0.2 to 0.5 oC per decade);
- There are many uncertainties in our predictions particularly with regard to the timing, magnitude and regional patterns of climate change, due to our incomplete understanding of: sources and sinks of GHGs;
- Our judgement is that: global mean surface air temperature has increased by 0.3 to 0.6 oC over the last 100 years...; The size of this warming is broadly consistent with prediction of climate models, but it is also of the same magnitude as natural climate variability.
Further reading
IPPC