Category Archives: Global Warming


As a non-native English speaker, I often encounter new words. One such word is “equivocation” (using the same word for different things or the use of such word in multiple senses throughout an argument, leading to a false conclusion). The first time I heard about it, I recognized it as something that is frequently used in global warming/climate change communication.

At the end of last week, when searching for something related to the consensus, I landed at the Skeptical Science page titled The 97% consensus on global warming (intermediate version). I am pretty sure that I must have read this before, but having “equivocation” at the back of my mind, gave it a new dimension.

As the title suggests, its subject is the 97% consensus. It starts from the statement of the Petition Project that “there is no convincing scientific evidence that human release of carbon dioxide will, in the foreseeable future, cause catastrophic heating of the Earth’s atmosphere”.

The Skeptical Science author calls this a myth and tackles it by explaining that a consensus of around 95% is found in papers like Cook et al 2013 & 2016, Oreskes 2004, Doran 2009 and Anderegg 2010. Also mentioned are the Vision Prize poll that basically found something similar and a list of scientific organizations that endorse the consensus.

I don’t know much about the Petition Project, but from the excerpt given in the Skeptical Science article, it is clear that the Petition Project statement is very specific. They claim that there is no consensus specifically on the catastrophic nature of global warming caused by human emissions.

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Define “AGW”

Spread over the Cook et al 2018 paper are the terms “anthropogenic climate change” and “anthropogenic global warming”. It is also mentioned a in table S2 of the supplementary material. I assume that “anthropogenic global warming” means that global temperatures are rising and humans have an impact. This seems to be supported by the consensus claim from the paper (my emphasis):

There is an overwhelming scientific consensus that humans are causing global warming (Cook et al 2016), with a number of studies converging on 97% agreement among publishing climate scientists or relevant climate papers (Doran and Zimmerman 2009, Anderegg et al 2010, Cook et al 2013, Carlton et al 2015).

That is a far cry from the previous statement in the Alice in Wonderland paper. In that paper, the claim was made that there is a consensus that global warming “presents a global problem”. A claim that obviously was unsupported by the papers that were referenced.

At least he skipped the “dangerous” part of the claim. It is now in line with what the referenced papers researched. As explained in the link above, the referenced papers investigated the claim that global temperatures are rising and that humans have an influence in this. Not whether it is dangerous. Not whether something should be done about it.

However, I don’t think that the term “AGW” is used in this way in the paper. This sentence in the abstract makes me think that he means something different (my emphasis):

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Global Warming: the definition that fits everything

After the early winter with heavy snow in the North-East of the US, the debate again raises whether this is a result of global warming. On the one side there is the belief that this early winter weather in the North-East of the US is linked to global warming and on the other side there is the remark that one can not have it both. And every position in between.

“But”, would you say, “Couldn’t it be perfectly possible that global warming causes warming as well as snow?”. In a way, that is entirely possible. Sure, if global warming is real this could mean local temperatures go up, maybe even also droughts. Not hard to understand. When because of a polar vortex, cold air blows across a warmer water surface this will produce snow, maybe even lots of it. That is a known phenomenon.

It is of course a bit more complicated than that. The big question is: what is our definition of “global warming”? And do we all use the same definition?

Surprise, surprise, we don’t.

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Hooray, government policies may have slowed down global warming!

After a week in the South of France I am back at home and it is time to catch up on the news. One of the news stories that drew my attention was the UK Energy Minister, Baroness Sandip Verma, claiming that policies might play a role in curbing rising temperatures. See also the transcript of the debates in the House of Lords of October 27, 2014. The answer came after Viscount Ridley questioned when warming would start again:

My Lords, does my noble friend the Minister agree that the fifth assessment report of the Intergovernmental Panel on Climate Change has confirmed, in the same words, that there has been a “hiatus” in global warming for at least the past 15 years? Will she give us the opinion of her scientific advisers as to when that hiatus is likely to end?

In fact not a bad question, we hear all the time that the science behind global warming is clear. Wouldn’t that be a nice test to see how clear it really is?

But the answer was not exactly what I was expecting:

My Lords, my noble friend raises a couple of issues that we would dispute in a longer debate. What we do recognise is that a change in weather patterns is happening across the globe and that climate change is occurring; it may have slowed down but that is a good thing, and it could well be that some of the measures we are taking today have helped that to occur. If we are to respond seriously to climate change and changing weather patterns, we need to be able to put in place things that mitigate and adapt to those different patterns.

It reminded me about myself some 6 years ago. My switch from believer towards skeptic started with the question whether climate policies made a change in the form of a colder autumn. I know, I know, I was very naive at that time. But it was the beginning of a search that cumulated in this blog. The question made me think and in the end reconsider what I thought was obvious.

It clearly didn’t have the same effect on the Minister. The statement that the global warming hiatus might be related to some of the decarbonization measures is of course utter nonsense. There is one tiny little problem with his statement: until now CO2 was claimed to be CAUSING global warming and despite all the measures that have been taken, global emissions are still INCREASING.

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Going to Bordeaux just by staying at home

In today’s newspaper (Het Nieuwsblad) I found a small article on the last page about extreme weather and global warming. At first it made me roll my eyes…yet another climate report…sigh. But when reading the article I was very surprised it even reported on possible advantages of global warming (assuming those predicted changes are actually true of course).

The origin seemed to be the The KNMI’14-climate scenarios and Climate Scenarios, four scenarios based on recent results of climate research and the newest report of the IPCC.

I found other newspapers that reported on it, for example More extreme weather: winter in the Netherlands will be like winter in Bordeaux (in Dutch). That title caught my attention, it let me think about a post I wrote a month ago after a week in the South of France: How could the French ever survive in the South of France?. In which I explained that I wasn’t really impressed by the “worrying” thought of us, Belgians, having the climate of the South of France.

The same weather as in Bordeaux, that is something that wouldn’t impress much people in this region. If I compare this with the global warming reporting until now, this is rather soft. Am I getting weak or is something changing in global-warming reporting?

Global Warming as distracter

A week ago I heard the news that the Kiribati man who was seeking asylum in New Zealand because “rising seas and environmental risks caused by global warming” had lost his appeal. To recall: he came to New Zealand in 2007 and was ordered to leave the country. He then claimed he couldn’t safely return to his country because of global warming and the sea level rise. Asylum was refused on the grounds his claim fell short of the legal criteria, such as fear of persecution or threats to his life. He then appealed the decision. Now he fears deportation because he lost the appeal.

The verdict was of course not based on science or facts, but on juridical analysis. Juridically he didn’t fulfill the current definition of a refugee although his lawyer took great effort in trying to change the definition of “persecution”. They now consider taking the case to the United Nations Human Rights Committee.

One question kept buggering me: how could such a case ever been started? If we look at the sea level rise in the Kiribati area, it is remarkably stable. A study found that some islands there even increased in size. Yet, now someone is pleading that his country is not able to care for its inhabitants anymore and will be engulfed by an assumed rise somewhere in the future. Without seeing an actual rise. Looking at the data and considering that these are not islands but atolls, should at least put some question marks with these claims.

It made me think about another situation. Last year at the Warsaw summit, the developing countries walked away from the negotiations because their expectations of being compensated for the historic emissions of the developed world were not fulfilled. Scientists, politicians and the media told for many decades that CO2 is the culprit of extreme weather and therefor there is a need to limit its emissions. The developing countries took that for granted and claimed compensation because of this wrongdoing of the developed countries.

None of these are based on an actual threat, but on assumptions, on mathematical models, but also on politics. The overstatements have their origin in keeping fear alive. The fear that many bad things could happen, so to influence other people/politicians in supporting their solution. Fear is of course a powerful political instrument, but playing with fear can have unintentional consequences.

After stating CO2 responsible for all things bad and even boldly stating that our past emissions amplifying and/or even causing storms such as Haiyan, it would come as no surprise that developing countries make an emotional appeal for compensation of this injustice. Even if there is no link found between our emissions and storms. Yet politicians keep on feeding this idea in an desperate move to influence decision making. What would happen in the next summit in Paris 2015 is rather predictable.

After stating CO2 responsible for (global) sea level rise, it would come as no big surprise that inhabitants of atolls declare there is no future for them and they need the money or a residence in the developed world. Even if sea level is stable in their area. It has nothing to do with the science or the facts. We made it very easy for them for them to come to such a conclusion.

Don’t take me wrong. Cebu and Kiribati have real issues that have to be met. Haiyan struck poor people that were not prepared. Helping them is a no brainer. Kiribati has an issue with overpopulation and more impact on the environmental than it can handle. But connecting them with global warming is distracting from the real issues and therefor is not going to help to solve them.

Is Anthropogenic Global Warming by definition Catastrophic?


It have been said many, many times before. There supposedly is a scientific consensus that increasing anthropogenic CO2 concentrations in the atmosphere are responsible for most of the warming we experienced. It has been said in many variants and is said to justify (immediate) action on climate change.

In the two last posts I wondered what exactly there is a consensus about? My take is that it might be something different than what is communicated.

A couple weeks ago I looked at the Crossing the 2014 Climate Divide: Scientists, Skeptics & the Media video. The first three posts of March were about the first part starring Suzanne Goldenberg (The Guardian). In it also Naomi Oreskes was present. She talked about her experiences with the skeptics and how she entered the climate debate. It was mostly about the extremists, you have them on both sides, not really interesting for me. But it was also about how she came to believe and documented the “consensus”. That was more interesting. Her work is widely cited by many alarmists as a confirmation of the existence of the scientific consensus on global warming.

This is how it was presented: BEYOND THE IVORY TOWER – The Scientific Consensus on Climate Change. What she did was downloading the abstracts of 928 peer reviewed articles which she found when entering the key words “global climate change” for the period of 1993 until 2003 in the ISI database (Institute for Scientific Information).

The question she had was how many papers disagreed with the position of the US National Academy of Science and the IPCC:

Human activities … are modifying the concentration of atmospheric constituents … that absorb or scatter radiant energy. … [M]ost of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations

The conclusion was none: 75% of the articles accepted the “consensus” and 25% were taking no position. This is a subjective thing. Some others have tried this and came to other conclusions. But I have no access to the ISI database, so I will not go there. I will try to look at the method and the definition to see how far I get.

The first statement is something everybody can agree with, at least I have not seen someone disagreeing with that. The Keeling curve learns that the CO2 concentration is rising, at least since 1958 when measurements began. Nothing controversial here. But at such it doesn’t proves much.

Greenhouse gases absorb or scatter radiant energy. Also nothing controversial here.

The last statement seems detailed at first glance, but is a bit more ambiguous:

  • Most of the warming: most is rather ambiguous. It is at least from somewhat above 50% until a bit less than 100%. Let alone how to quantify “most” in an abstract. Okay, let’s assume that this is possible and it is reliable enough to measure the abstracts.
  • Likely: according to the IPCC this means larger than 66%. Okay, there is at least 66% chance that “most” of the observed warming over the last 50 years is due to increase of greenhouse gas concentrations. That means there is 34% or less chance that “most” of the observed warming over the last 50 years is NOT due to the increase of greenhouse gas concentrations.

However, the obvious missing part is the fact that nowhere is stated that this increase is dangerous or leads to catastrophic changes in our climate, therefor needing immediate action. The only thing this statements tell us is that scientists are certain that there is an increased concentration of CO2 in the atmosphere (which is true), that this absorbs or scatters radiant energy (which is also true) and this could mean that part of this increase is caused by our emissions.

That is really uncontroversial. All the skeptics that I know of agree with that. They acknowledge that there is more CO2 in the atmosphere because of our emissions, that it is a greenhouse gas and it will give more warming, everything else being equal. There are some differences though. Like how sure are we about the warming considering the scarce climate data we accumulated from the past? How sure are we about the projections of the temperatures into the future? How sure are we about a warmer world worse than a cooler world? Etcetera. Nothing in this position point out that this warming is bad, but that is how it is marketed.

The measured consensus is about something uncontroversial and has absolutely nothing to do with the extent of the assumed danger associated with this warming, nor with the necessity of action to prevent this increase in warming.