A group of MPs has today released a report examining the work of the Intergovernmental Panel on Climate Change (IPCC) – the UN body tasked with assessing the state of climate change science. The report concludes that the IPCC presents “a clear and unambiguous picture of a climate that is being dangerously destabilised.”

The report from the House of Commons Energy and Climate Change (ECC) committee completes a nine-month long investigation, during which a number of witnesses were called on to give evidence on the robustness of the IPCC’s workings and conclusions.

The inquiry came mid-way through the publication of a series reports on climate change released by the IPCC over the course of a year.

Minutes released with the report show efforts by two climate skeptic MPs – Graham Stringer and Peter Lilley – to change the report to conclude that the work of the IPCC was unsound in various ways. But the committee rejected the changes – finding no cause for concern with the way the IPCC operates or the conclusions it reaches.

“The best available summary”

Last September, the IPCC released part one of its Fifth Assessment Report (AR5).

Looking at the physical science of climate change, it concluded the land and oceans are warming, ice cover is melting and our weather is getting more extreme. It also concluded human activity is responsible for a large part of the changes we’ve seen since the late 20th century.

The committee today described the AR5 as “the best available summary of the prevailing scientific opinion on climate change currently available to policymakers”, noting that:

“The overall thrust and conclusions of the report are widely supported in the scientific community.”

Several climate skeptic personalities gave evidence to the committee, and the report deals with the criticisms they made of the organisation.

For example, take the charge that IPCC authors “may let their political persuasions (especially towards environmental activism) cloud their judgement as to what should and should not be included in the reports.”

ECC finds no evidence to support such a criticism:

“We are satisfied there was no systematic bias of any kind, be it financial, political or otherwise that would jeopardise the accuracy of the reported scientific conclusions.”

The report says it also finds “no convincing evidence” that challenges the IPCC’s estimate that most of the changes recorded in the latter half of the 20th century are driven by human activity.

On climate skeptic criticisms levelled at climate models and their projections of future warming, the report says:

“Under closer scrutiny, many of the criticisms of model projections appear unfounded â?¦ generalised statements concerning their reliability do not reflect the complexity and diversity of the models.”

However, it adds that the government “should commission a strategic review of UK modelling facilities to discern how current computing capacity could be used more effectively to reduce remaining uncertainties.”

Dealing with criticism

Today’s report acknowledges the policy implications of the IPCC reports means they are subject to heavy scrutiny. The committee also suggests the IPCC has come under fire in the past for not satisfactorily dealing with criticisms levelled against it. But they suggest:

“The IPCC has responded extremely well to constructive criticism in the last few years and has tightened its review process to make AR5 the most exhaustive and heavily scrutinised assessment report to date.”

Later on, the report says:

“The process by which the IPCC’s assessment report is produced and agreed has improved considerably since the release of the 4th assessment report in 2007, mostly as a consequence of a review by the Interacademy council (IAC) in 2010 … The IPCC has put a series of measures in place to help minimise the risk of errors creeping in, and quickly rectify them if they emerge.”

Uncertainties in context, even greater transparency

How the IPCC deals with uncertainties in the science was a major focus for parts of the oral evidence sessions.

On that topic, the report concludes:

“As in all areas of science that involve highly complex dynamic systems, there are uncertainties. But these uncertainties do not blur the overwhelming clear picture of a climate system changing as a result of human influence.”

The committee does make some a couple of suggestions for improvements. It suggests the introduction of a “common language to describe uncertainty” would “help maintain consistency” across different reports.

The IPCC already has a pretty comprehensive and open review policy, as the report acknowledges. But it also recommends that more oversight could be built in:

“We believe the IPCC would benefit from increasing the level of transparency by recruiting a small team of non-climate scientists to observe the review process from start to finish â?¦ the testimony of this independent team would improve the credibility of the report when it is released, and potentially protect it from any unnecessary and unfounded criticism.”

The report also notes that there isn’t much agreement on how the IPCC should develop in the future, but that some scientists – particularly those involve in writing the IPCC report – suggest smaller, more frequent reports might be more manageable and responsive to new science.

Time to heed the warnings

According to today’s report, the conclusions from the investigation boil down to the fact that “there is no scientific basis for downgrading the UK’s ambition to reduce greenhouse gas emissions.”

In fact, the report adds:

“The government and the international community must heed the IPCC’s warning and work to agree a binding global deal in 2015 to limit climate change to manageable levels.”

While the report isn’t likely to change the minds of those who dislike the IPCC or climate scientists in general, it does appear the ECC committee didn’t find anything particular convincing about their arguments.