jennifer

Not so long ago I republished a letter from 60 ‘global warming skeptics’ who wrote to the new Prime Minister of Canada asking for more public consultation on climate change issues and explaining that climate change can be natural, click here to read the blog piece.

Now 90 ‘global warming believers’ have written to the PM of Canada:

An Open Letter to the Prime Minister of Canada on Climate Change Science

April 18 2006

The Right Honourable Stephen Harper, P.C., M.P.

Prime Minister of Canada

Ottawa, ON K1A 0A3

Dear Prime Minister:

As climate science leaders from the academic, public and private sectors across Canada, we wish to convey our views on the current state of knowledge of climate change and to call upon you to provide national leadership in addressing the issue. The scientific views we express are shared by the vast majority of the national and international climate science community.

We concur with the climate science assessment of the Intergovernmental Panel on Climate Change (IPCC) in 2001, which has also been supported by the Royal Society of Canada and the national academies of science of all G-8 countries, as well as those of China, India and Brazil. We endorse the conclusions of the IPCC assessment that “There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities” and of the 2005 Arctic Climate Impact Assessment that “Arctic temperatures have risen at almost twice the rate of those in the rest of the world over the past few decades”.

Climate variability and change is a global issue and the international IPCC process for assessment of climate science, with its rigorous scientific peer review processes, is the appropriate mechanism for assessing what is known and not known about climate science. Many Canadian climate scientists are participating in the preparation of the IPCC Fourth Assessment Report which will be completed in 2007.

The following points emerge from the assessments and ongoing research by respected Canadian and international researchers:
• There is increasingly unambiguous evidence of changing climate in Canada and around the world.
• There will be increasing impacts of climate change on Canada’s natural ecosystems and on our socio-economic activities.
• Advances in climate science since the 2001 IPCC Assessment have provided more evidence supporting the need for action and development of a strategy for adaptation to projected changes.
• Canada needs a national climate change strategy with continued investments in research to track the rate and nature of changes, understand what is happening, to refine projections of changes induced by anthropogenic release of greenhouse gases and to analyse opportunities and threats presented by these changes.

We have supplied justification and more detail for each of these points in the accompanying documentation.

We urge you and your government to develop an effective national strategy to deal with the many important aspects of climate that will affect both Canada and the rest of the world in the near future. We believe that sound policy requires good scientific input.

We would be pleased to provide a scientific briefing and further support, clarification and information at any time.

Yours sincerely:

Signed by 90 Canadian climate science leaders from the academic, public and private sectors across the country.

For a list of the science leaders and also supporting background information click here.

And there is editorial comment at CNC, click here and more opinion at Canada’s National Post, click here.

Following my blog post titled ‘Richard Lindzen on Hockey Sticks’ there was some discussion about Richard Tol’s views on various issues relating to economics and the Intergovernmental Panel on Climate Change. Various commentators at the thread where quoting Dr Tol in support of their position. Dr Tol has provided the following response:

“Ian Castles and William Connelley had a discussion about what I said and did not say. Here is my version.

If one assumes convergence of per capita income, and one measures income in purchasing power parity (PPP) exchange rates, then projections of global carbon dioxide emissions are lower than in case one measures income in market exchange rates (MER).

This is the original Castles and Henderson critique of IPCC SRES.

However, emission intensities are also assumed to converge, which partly offsets the above effect.

This was pointed out by Manne and Richels, and by Alfsen and Holtsmark, while Castles and Henderson admitted their initial omission.

As a result, switching from MER to PPP reduces global carbon dioxide emissions, but by an amount that is small compared to the uncertainty about future emissions.

That is, if one is interested in long-term, global climate change, the Castles and Henderson critique is of minor importance.

However, one should worry about the fact that the IPCC, first, made a very basic error and, second, is unable to admit that and correct its way.

If one is interested in climate policy, the Castles and Henderson critique does matter, because the small drop in global emissions is almost entirely due to China and India. The OECD thus shoulders a larger part of the responsibility. The argument of the US Senate, that climate policy without China makes no sense, cuts less wood.

If one is interested in climate impacts, the Castles and Henderson critique does matter, because projected economic growth is slower in developing countries, and vulnerability is larger as a result. Although warming would be slower, impacts may in fact be larger.

If one is interested in regional climate change, the Castles and Henderson critique does matter, because future emissions of sulphur would be different as well, probably higher.

In sum, Castles and Henderson raise five issues, only one of which is of minor importance.

By the way, my reading of the state-of-the-art in economics is that (a) income should be measured in PPP nor MER; (b) there is neither theoretical nor empirical support for the assumption of unconditional income convergence; (c) there is limited empirical support for the assumption on energy intensity convergence.

Richard Tol”

Dr Tol is the Michael Otto Professor of Sustainability and Global Change in the Departments of Geosciences and Economics at the Hamburg University, Hamburg, Germany.