Are Climate Change Models too Inaccurate to be Useful in Policy-making?

This blog post covers the report written by Griffin Carpenter, commissioned under the New Economics Foundation. The report seeks to debunk those who deny the fact (there is 95% certainty according to the IPCC) that humans have been the main cause of global warming from 1960 to present.

According to the report, instead of outright denying global warming, those who have been trying to undermine it, have done it by claiming the whole thing is uncertain. A recent Oxford study found that 80% of articles covering the topic contain uncertainty. This figure seems to suggest that many journalists unintentionally seem to undermine the effort made by scientists in warning the people when they use words that suggest that climate change is still uncertain. Undermining also happens very intentionally when criticising the figures given by the foremost panel on climate change.

The Intergovernmental Panel on Climate Change (IPCC) draws from the work of thousands of scientists from over 120 countries and their forecasts are internationally accepted as the most comprehensive and authoritative climate predictions available. IPCC has a 95% estimated certainty that humans have been the main cause of global warming from 1950 to present. To put this into context, it higher than the certainty that vitamins are good for you.

One of the many ways, the climate change studies are undermined is by claiming that climate forecasts are entirely inaccurate.

The report first seeks to define accuracy and does so as; a forecast that is both unbiased (the repeatability of the result) and precise (closeness to the actual value). Carpenter admits that very few models fall into both the unbiased and precise category. This is because it is too complex. Therefore, precision can be secondary to understanding a general trend.

When comparing forecast with the actual figures from 1995 to 2013, climate data points are shown to be largely in line with the projections made in 1995. In fact, it is both unbiased (it followed the trend predicted) and precise (it was largely within the forecast range).

This shows that the media largely exaggerate and jumped on the few mistakes that have been made by IPCC. Another claim made is that the models are not to the correct standard of accuracy for policy-making. Governments decision makers constantly use the predictions of professional economists who use complex economic models. Carpenter now seeks to find out if climate change models are as reliable as economic and social indicators already in use. If they are, it follows that they will be at the standard required to be used in policy making.

When comparing IPCC models with commonly used long term government measures (the ONS population forecast, the forecast of the HM Treasury’s debt/GDP ratio, and the US Energy information Administration oil price forecast) showcases a lot of inaccuracies in the economic measures.

Governments around should be confident in using the data to make policy decisions so that we can take steps to improve the world around us.

The report is convincing and successfully debunks claims that climate forecasts are inaccurate or not accurate enough to be help in policy making.