500 scientists?

14.06.2020 17:27

It is interesting: An open letter from 500 scientists, titled "There is No Climate Emergency", sent to United Nations (UN) Secretary-General António Guterres before the UN Climate Summit in New York (2019), is still circulating in the Czech social and media space (HERE). Eight months ago, I wrote a critique of this pamphlet, and I am quite surprised that it has become a vision of a new sceptic movement (CLINTEL).

However, the group of 500 scientists and professionals accompanied the letter with a justification in six paragraphs, outlining the issues that do not stand up to the debate between scientists and professionals in the context of climate change. Now judge for yourself:

1. Warming is caused by natural and anthropogenic factors

Yes, this is certainly true, but the authors forgot to add that natural factors (e.g., Milankovitch cycles) have always been responsible for changes in the geological past and ancient history; nowadays, however, climate change is manmade – affected by the changes in the chemical composition of the atmosphere and quality of earth's surface. No eligible scientist can seriously surmise the logical construction that the climate is changing naturally today because it naturally changed across history.

2. Warming is slower than expected

Climate projections are always prepared in accordance with so-called emission scenarios, which describe the development of humanity and the planet in the coming decades (estimation of greenhouse gas production, population growth, changes in afforestation and land use, energy consumption and other factors). Yes, the current warming is slower than was assumed by the pessimistic projections. But, at the same time, it is faster than expected by the average estimates that emerged from these projections (see FAR IPCC 1990). It is certainly faster than the historical changes caused by natural factors. I am afraid to assume that the statement was based on a comparison of projections with satellite and balloon measurements in the lower troposphere. This completely nonsensical graph is still very popular in the sceptic community.

3. Climate policy uses insufficient models

Of course, no model is 100% accurate. Climate models are probabilistic and present comparatively lower (optimistic) or higher (pessimistic) estimates. It is wrong to rely only on pessimistic estimates, and it is sad that the authors did so in the previous point; neither the politicians nor active citizens should do so in promoting climate action. During its geological evolution, planet Earth created an important carbon balance, which has maintained a balanced CO2 content in the atmosphere, in the range of about 180–280 ppm over hundreds of thousands years. However, man has upset this balance and increased the concentration of CO2 in the atmosphere to the current value of 410 ppm, over the past 200 years. This level is not the main problem for the atmosphere; the problem is the rate at which the amount of CO2 in the atmosphere is increasing.

4. CO2 is the basis of life on earth

I do not understand, what has led 500 scientists and professionals to tell the world that CO2 is an important part of photosynthesis. This has been taught in primary schools and no one has ever questioned it. It is true that the higher CO2 content promotes the formation of green matter, and the planet is greening, as evidenced by the satellite measurements in many places; however, satellite measurements have also confirmed that the planet is browning, as water resources are being depleted by faster plant growth. Unfortunately, owing to warming, the planet is also blueing, as the floating ice of the Arctic is melting at a rate faster than that at which the areas of floating ice are expanding around Antarctica. When it comes to increasing yields in agriculture, I would look for the cause in agro-technical processes and in chemistry, not in CO2.

5. Warming does not increase natural disasters

This could be discussed. Extremes of weather have always been interlinked, as we find in the history of many major catastrophes. However, if someone does not see that hurricanes occur suddenly not only during the so-called hurricane season but almost all year round, and that they bring more precipitation and higher wind speeds, then let them study the statistics of extreme events in Czechia. We have floods and storms more often, droughts are longer and our great-grandmothers considered two days with a temperature of 25 °C as a heatwave.

6. Climate policy must respect scientific and economic realities

It is admirable that 500 scientists and professionals have decided to support Greta Thunberg, who also calls on politicians to listen to scientists. I would expect them to be more specific in stating that moving economies towards carbon neutrality is harmful. This is a topic we should discuss today rather than wasting time in false discussions about the benefits of CO2, cherry-picking pessimistic scenarios or relativizing natural disasters.

It is not a problem that 500 scientists and professionals from fields that usually do not have much in common with climatology have signed this call. They are people with vast experience in science, politics and other fields, and their views are certainly important. The problem is in the 14 names mentioned at the beginning who, I suppose, created the text of the letter. None of them are climatologists – the only meteorologist is Prof. Lindzen. I cannot imagine the Intergovernmental Panel on Climate Change (IPCC) preparing its outputs in the same way. IPCC assessment reports are always written by scientists who are very close to the topic. Scientists in the author team can be nominated by anyone, but their professional CVs and scientific outputs are essential.

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