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Research article

A simple climate change projection for the concerned public

Author
  • Philip John Wilson (Independent)

This article is a preprint and is currently undergoing peer review by UCL Open: Environment.

Abstract

The Intergovernmental Panel on Climate Change (IPCC) addresses policymakers with elaborate projections that are difficult for most people to understand. The simplest model is the recent trend in mean annual global warming, and the simplest projection is the extrapolation of the trend line into the future. Amid the annual variation the trend line is an index of the global mean warming at any one time, whereas the IPCC’s method of estimation (the 20-year running mean) is retroactive. Until now the trend has been almost linear. Projected linearly into the future (a conservative projection if warming has begun to accelerate), the 50-year data give results similar to the IPCC projections to mid-century, the 20-year data, which have a slightly more rapid rate of change, to less cautious published projections. A mean warming of 1.5C would be reached in 2032 and 2029 respectively. To plot the graphs, and to decide how to project the trend lines into the future, is a simple exercise that avoids much complexity and is open to almost anyone to understand or to perform for themselves. It fosters critical thinking, lessening the gap between the public’s perception of climate change and that of climate scientists.

Keywords: Intergovernmental Panel on Climate Change, public understanding of science, climate change, global warming, global mean warming, simplicity.

Preprint Under Review
License
Creative Commons Attribution 4.0

 Open peer review from Maria Turkenburg-van Diepen

Review
Your review
Please focus on the following points in your comments.
1. Is the article relevant to UCL Open Environment aims and scope, as set out above?
2. Does it offer an original contribution to the field? Is it breaking new ground? If so, how?
3. Does it engage with recent scholarship?
4. What are the strengths of its argument and analysis? Do you have suggestions for improvement?
5. Is the overall style and presentation good? Do you have suggestions for improvement?
6. Is the article’s length appropriate for what it has to say? Suggestions for shortening papers that extend over 8,000 words (excluding references) are welcome.

Ad 1.
I think the article is relevant, but I do not know how much new knowledge it adds. I assume that many people around the world are trying to make the IPCC reports accessible to the wider public. There is no mention in this article about other efforts in this direction.
Ad 2.
See above. I have personally not seen literature looking to use trend lines in this way, but I can’t help but think that it exists.
Ad 3.
The article definitely engages with a wide range of literature, including academic scholarly literature.
Ad 4.
I think the argument and analysis are largely sound, but not presented in a way that make it easy to understand. The figures are clear in themselves, but the argument made on the basis of them is about the steepness of the trend lines, which look exactly the same on first glance, most likely because of the scale used on the axes. There must be ways that make this clearer. I wonder whether a collaboration with an education expert might improve the presentation of the argument through figures and text. If a teacher can explain it to a teenager, it is probably appropriate for the general public.
I was not totally enamoured with section 3.2 (non-linear extrapolations). There was a largely emotionally laden, although mostly thoroughly referenced, summing up of parameters which may or may not contribute to the need for non-linear extrapolations, which, in my eyes, did not argue the case appropriately. And there was one sentence in that section which I did not understand at all:
“Climate-related loss and damage has to be made good”. I wondered where that sentence came from, what it means, and who thinks so.
I am also struggling with the use of the term ‘less cautious’. I find it confusing in this context. It started to fall into place for me a little bit more when I read about statistical confidence. But as the author is keen to help public understanding, I think resorting to statistical confidence is not helpful, even if it is academically sound.
Ad 5.
See Ad 4.
Ad 6.
I read the article with interest, and I think there is something in it. Seeing as it represents one independent researcher’s work, it deserves attention somehow. But in its present form I am doubtful that it will make much of an impact.

Note:
This review refers to round of peer review and may pertain to an earlier version of the document.