A consensus is usually established when one explanation is more convincing than alternative accounts, convincing the majority. This is also true in science. However, science-based knowledge is also our best description of our world because it is built on testing hypotheses that are independently reexamined by colleagues.
It is also typical that there are a few stubborn people who think they know better than the rest. When it comes to climate science, there is a small group of people who refuse to acknowledge the facts that have convinced almost the entire scientific community. Most of these contrarians are not even scientists.
But there are also about 500 scholars who recently have come forward and signed a declaration at odds with the scientific consensus, claiming “there is no climate emergency”. They represent a tiny fraction of the scholar community dismissing man-made climate change – by comparison, there is about 20,000 participants on the annual meetings of the American Geophysical Union.
A press conferences has been scheduled on Friday October 18th in Brussels, Rome and Oslo in order to promote the declaration. The intention behind the declaration is to influence the EU and the UN.
Most of the academics who signed the petition have no or little experience within climate research (check Google Scholar). Some of the signatures also have connections with political think tanks.
The message of the declaration is the same that the contrarians have repeated over and over again – but repeating it doesn’t make it more true.
I and some colleagues have examined the most common contrarian papers on climate change and have found that all of them were based on flawed methods/analysis (see previous post Let’s learn from mistakes). Some of the people who signed this petition have demonstrated their incompetence – the proof is in the papers that I and my colleagues reexamined in that study.
We cannot expect every scientist to have the same understanding, especially when it comes to scientific disciplines other than those in which they have professional experience. When they dismiss evidence on matters in an unfamiliar discipline without a convincing explanation, then they demonstrate a lack of respect for both science and the wider public.
They obviously don’t care whether people get true facts of false ideas. Below, I’ll try to explain why their arguments still do not convince.
The following statement is misleading:
“The geological archive reveals that Earth’s climate has varied as long as the planet has existed, with natural cold and warm phases. The Little Ice Age ended as recently as 1850. Therefore, it is no surprise that we now are experiencing a period of warming. Only very few peer-reviewed papers even go so far as to say that recent warming is chiefly anthropogenic”
It is true that Earth’s climate has changed over the past, but such changes have had specific physical causes, which are reasonably well understood.
There have been changes in the shape of the continents, formation of mountain ranges, changes in atmospheric composition, changes in Earth’s orbit around the sun (the Milankovitch cycles), changes in the sun, volcanic activity, and changes in ocean currents, all of which have influenced Earth’s climate.
As for the “Little Ice Age”, it was very different to the present global warming. It had a more regional character and was not as synchronised on a global scale as the ongoing climate change.
The scientific documentation of past changes in climate is one of the ways that we know that that the climate is sensitive to changed conditions. The Earth has never been as closely monitored as today, especially with the help of satellites and advanced modern instruments, giving unprecedented amounts of high-quality data.
This monitoring shows that the conditions that caused climate change in the past are absent today, except for the increases in greenhouse gases. The IPCC reports provide lists of peer reviewed papers on the global warming.
The following statement is incorrect:
“The world has warmed at less than half the originally-predicted rate, and at less than half the rate to be expected on the basis of net anthropogenic forcing and radiative imbalance. It tells us that we are far from understanding climate change.”
Indeed, comparisons between simulated and observed global mean surface temperatures indicate a good correspondence.
I can believe that the people who signed the petition don’t understand climate change, but they should speak for themselves. The rest of the science community has a fairly good understanding.
The fact that we can write computer code based on the fundamental laws of physics that is able to reproduce phenomena we observe on Earth, indicates that we do understand the climate system. See the description of climate models on both Carbonbrief.org and TED.com.
The following statement is incorrect:
“Climate models have many shortcomings and are not remotely plausible as policy tools. Moreover, they most likely exaggerate the effect of greenhouse gases such as CO2. In addition, they ignore the fact that enriching the atmosphere with CO2 is beneficial.”
The scientific knowledge underpinning climate policies is established both from observations as well as the laws of physics and climate models.
The global climate models share common description of the atmosphere with weather forecast models used on a daily basis to provide operational weather warnings.
All climate models have been evaluated and tested, and they do reproduce the observed global warming as seen with the observations.
The concentration of greenhouse gases in the atmosphere is increasing. Their physical properties can be established accurately through lab studies.
Carbon Dioxide (CO2) is a greenhouse gas which is a byproduct from the consumption of fossil energy, and the increase in the atmospheric CO2 concentrations represents approximately 40% of the total amount produced from the exploitation of fossil fuels.
The CO2 bears a fingerprint that connects the increased amount to coal, oil and gas, in terms of the isotopes carbon-13 and carbon-14, as well as the comparable concentrations of oxygen and nitrogen and ocean acidification.
The climate models reproduce the observed sensitivity, as shown in Benestad and Schmidt (2009) and the figure below.
The following statement is irrelevant:
“CO2 is not a pollutant. It is essential to all life on Earth. Photosynthesis is a blessing. More CO2 is beneficial for nature, greening the Earth: additional CO2 in the air has promoted growth in global plant biomass. It is also good for agriculture, increasing the yields of crops worldwide”
Water too is essential to all life on Earth. Too much is not good, such as flooding or drowning.
The following statement is incorrect:
“There is no statistical evidence that global warming is intensifying hurricanes, floods, droughts and such like natural disasters, or making them more frequent. However, CO2-mitigation measures are as damaging as they are costly. For instance, wind turbines kill birds and insects, and palm-oil plantations destroy the biodiversity of the rainforests.”
CO2 has an indirect effect on extreme weather conditions through increasing the greenhouse effect and changing Earth’s hydrological cycle. It is well-established that increased surface temperatures lead to increased evaporation and water vapour in the atmosphere.
Water vapour is the main fuel for weather phenomena such as storms and rainfall. Global warming is also accompanied by changes to the large-scale circulation pattern, such as the Hadley cell, affecting both extreme rainfall in the tropics and drought conditions in the sub-tropics.
The observed number of record-breaking temperatures and rainfall provide statistical evidence for the weather becoming more extreme. One example is the increased probability of heavy precipitation.
The following statement is misguided:
“There is no climate emergency. Therefore, there is no cause for panic and alarm. We strongly oppose the harmful and unrealistic net-zero CO2 policy proposed for 2050. If better approaches emerge, we will have ample time to reflect and adapt. The aim of international policy should be to provide reliable and affordable energy at all times, and throughout the world.”
There is ample evidence of changing risks connected to weather, with more heatwaves and more extreme rainfall.
The global mean sea-level is rising and coral reefs are dying. Glaciers providing predictable water supply are melting, such as in the Himalayas. The consequences for ecosystems and agriculture are dire.
The insurance sector is already affected, and the consequences from climate change will increasingly disrupt new sectors such as agriculture, water management, transport, tourism, and trade.
There will be regions where people no longer will be able to reside and there will be increased levels of migration and conflicts connected to climate change.
Rather than pushing a petition, the contrarians should present scientific evidence for their view. If such evidence exists, it needs to be transparent so that others can reexamine it and get swayed by the information. So far, the typical contrarians (and one of the signatures) have preferred not to disclose their work.
There have already been some reactions to this petition, e.g. on Climatefeedback.org. It was also preceded by a similar Italian “pro-fake-news” petition (signed by more or less the same Italian contrarians as this version) that prompted a response from Italian scientists.
The claims presented in the petition signed by 500 contrarians is the strongest case the contrarians can muster against climate science. In other words, the best shot from the majority of world’s supposedly prominent academics known to have an alternative opinion (i.e. the majority of a tiny minority).
Obviously, there is not much convincing evidence against anthropogenic climate change.
- R.E. Benestad, and G.A. Schmidt, "Solar trends and global warming", Journal of Geophysical Research, vol. 114, 2009. http://dx.doi.org/10.1029/2008JD011639