Sir John Bedddington, provides the introduction to a summary of “The Science of Climate change” on  UK Business Department website. He states

            “The fact that uncertainty exists in climate science, as it does in other fields, does not negate the value of the evidence – and it is important to recognise that uncertainty may go in both (or a number of) directions.”

This may be true in a new field, but there is evidence that where the consensus is concerned, when assumptions have to be made, or choices made between different scientific conclusions, there has been a very strong bias towards the more alarmist conclusions. For instance,

1. The emphasis on positive feedbacks;
2. The over-statement of climate sensitivities;
3. The promotion of the hockey stick as secondary verification of recent warming being largely due to anthropogenic factors.
4. Further there has been a public relations failure to challenge unsound science, or wild predictions, or false confirmations.
5. Neither have there been any consensus scientists standing up to emphasise that the model scenarios of future temperature changes are not forecasts

The consequence of recognising uncertainty means that an audit is required of the total picture. Each part of the science needs to be graded according to the certainties. Most certain is that a massive increase in greenhouse gases will, ceteris paribus, cause a rise in temperature. At the other extreme are predictions that within a generation the Arctic Ocean will be ice-free in summer, or the Himalayan glaciers will have vanished, or the Maldives will disappear beneath the waves. The rhetoric needs to be replaced by establishing the case on a scientific basis. It is not sufficient to say that there is uncertainty and move on as is nothing had happened. The presence of uncertainty severely weakens the claim that the science is established and settled. We should now see the consequences for policy.

Hattip to BishopHill