Confronted with a climatosceptic? 12 statements to qualify

Confronting ; a climatosceptic? 12 statements to qualify

A list to help you during your next family dinners.

In front of a friend who denies or minimizes the reality of global warming, you may be tempted to give up. The Rumor Detector examines 12 of the arguments from which it would nevertheless be possible to establish common ground, even with those who are said to be “ climatosceptics ”.

1. “ The climate has always warmed and cooled ”

Temperatures of course vary over the course of the seasons, years, centuries and millennia: this is an essential fact taken into account by all climatologists. In other words, they have never denied that the Earth has always warmed and cooled.

The problem is that the current disruption of the climate does not fit into the “ classic ” pattern of these natural variations. According to a study published in 2018 in PNAS, by 2030 we will reach a climate similar to that experienced by the Earth three million years ago. And if CO2 emissions continue to increase at the current rate, we could, as early as 2150, live in a climate similar to that which the Earth experienced 50 million years ago. That's unprecedented speed.

2 . “ CO2 is not toxic, since plants need it ”

It goes without saying that plants need CO2. If it is singled out in the context of climate change, it has never been because it was said to be “toxic”, but rather because it is a greenhouse gas. Climatologists therefore do not question the usefulness of CO2, but the increase in its concentration in the atmosphere, which directly affects the temperatures of the planet.

On the plant side, an increase in CO2 can stimulate their growth through photosynthesis. On the other hand, the climatic disturbances induced by this excess CO2 will have other consequences on them: rising temperatures, variations in humidity and nutrients available in the soil…

Taking into account all these factors, all of the studies conducted on this subject suggest that the climate balance will tip against plants.

3. “ CO2 only makes up a small part of the atmosphere ”

There's no doubt about that either: CO2 makes up a measly 0.041% of the atmosphere, or 414.72 parts per million (PPM) in 2021. But its increase isn't. less tangible. We have gone from nearly 280 PPM to over 400 PPM in less than a century and a half, and this rise is accelerating. the limit not to be exceeded to avoid irreversible consequences on the planet; however, in 2021, the experts recorded an increase of 2.58 PPM compared to the previous year. Therefore, if the trend continues, the Earth's atmosphere will reach this threshold of 450 PPM of CO2 in less than 15 years.

4. “ Water vapor is a bigger greenhouse gas than CO2 ”

This statement tells us nothing either: water vapor is actually responsible for around 60% of the greenhouse effect suffered by our planet. But a distinction must be made between greenhouse gases (GHGs) naturally present in the atmosphere and those released by human activities.

Water vapor is based on a “simple” physical balance: at a certain temperature, the atmosphere is capable of containing a certain amount of water. So when we turn on our kettle or dry our clothes outside, we don't contribute to global warming with excessive evaporation: thanks to the water cycle, this vapor will condense and fall as rain or snow, after about 9 or 10 days. The IPCC estimates that the water vapor of human origin, produced in particular by the irrigation of crops, is negligible compared to the natural evaporation of water.

Unfortunately for us, human activities release other GHGs than water vapour. For example, CO2, methane or nitrous oxide, which are problematic because they can remain in the atmosphere for several years, even several thousand years. It is this accumulation that endangers the climate.

However, with this accumulation, the global temperature of the planet increases, and with it, the capacity of the atmosphere to contain more water. As more water evaporates, the amount of water vapor in the atmosphere increases — further aggravating the greenhouse effect. This accumulation effect is also taken into account by the calculations of climatologists: without this effect, it is estimated that the warming power of CO2 would be halved.

5. “ There have always been species that have disappeared, it's part of nature ”

If, at all times, species have indeed disappeared from the surface of the globe, the rate at which they are disappearing at the moment raises fears of mass extinction. And even though such an event has already happened five times in the history of our planet, it is not something to be taken lightly. Especially since the current biodiversity crisis is largely caused by our actions, which lead to the destruction of ecosystems.

As early as 2004, a study published in Nature showed that climate change had already affected species on Earth over the past 30 years, and predicted a 15 to 37% extinction of species by 2050. Nearly 20 years later, the 2021 IPCC report came to provide details: it is 100 % of island species, 84 % of species living in the mountains, 12 % of continental species and 54 % of maritime species, which could be threatened with extinction due to climate change.

6. “ Species will adapt to global warming ”

The continuation of life on Earth should not be confused with the adaptation of current species. There have been living things on Earth for at least three and a half billion years, and there will likely continue to be, no matter what we do. But the ability of species to adapt to current global warming is a major research subject with large gray areas. It has for example been shown in a study published in Nature in 2019 that, while some species today manage to adapt their seasonal behavior to global temperature increases, global warming is nevertheless too rapid for their genetics to follow: the evolution of species takes place over millions of generations, and not over a handful of years. And these changes in seasonal behavior have their limits, because in the history of evolution, species have shown less tolerance to temperature increases, compared to colder climatic periods.

7. “ It's sad if species disappear, but that's not what will change our life ”

It is very risky to say that the decline of the biodiversity will have no impact on our societies. According to a study published in Science in 2011, the disappearance of a single species can weaken an entire ecosystem and lead, through a domino effect, to the decline of many other species. It can even lead to indirect consequences such as encouraging forest fires, the spread of disease or the proliferation of invasive species.

Thus, according to a 2016 report by IPBES (the UN group of experts on biodiversity), 75% of global agriculture relies on pollinating insects. “The living tissue of the Earth, essential and interconnected, is shrinking and fraying more and more”, said in a press release Professor Josef Settele, researcher at IPBES. “This loss is the direct consequence of human activity and constitutes a threat to the well-being of humanity in all regions of the world. »

There are even economists who, for several years, have been putting an “economic value” on nature, with the aim of estimating what we will lose if we do not protect these gains more.

8. “ Humanity has always survived, it will survive disasters ”

No scientific study has announced the disappearance of the human species because of global warming. But in addition to the financial costs caused by biodiversity loss, forest fires or extreme weather events, there will inevitably be loss of life. For example, the IPCC predicts that 48-76% of the world's population will be exposed to deadly heat waves before the end of the century, depending on the different temperature increase scenarios. If the climate experiences an increase of just 2°C, 800 million to 3 billion people will suffer from insufficient access to drinking water due to droughts. The World Health Organization estimates that between 2030 and 2050, climate change could cause 250,000 premature deaths each year due to malnutrition, disease and extreme heat. And according to the 2017 Lancet Countdown, between 25 million and 1 billion people will be forced to migrate because of climate change and the armed conflicts it will cause.

9.  Reducing emissions would be disastrous for the economy ”

The debate between protecting the environment and protecting the economy has been around for 40 years. No one denied that there would be costs. But before claiming that it would be “disastrous”, we must ask ourselves in relation to what: could doing nothing also result in a “disastrous” bill in the coming decades?

In its 2018 report, the IPCC points out that climate change will lead to economic crises during the 21st century, with a slowdown in the world economy and an overall increase in poverty. In concrete terms, the measures to be put in place to limit global warming would cost a developed country, on average, $127 to $295 billion per year between 2030 and 2050. winners when compared to the cost of future disasters, assuming the planet continues to warm at the current rate. In its latest report for 2022, the IPCC adds that the economic consequences of climate change will increase non-linearly with the temperatures reached: this means that, for each additional fraction of a degree, the risks for the economy will increase tenfold.

10. “ We are far from being the biggest polluters on a global scale ”

Although it seems to do well next to oil-producing countries like Qatar and its 50 tonnes of CO2 equivalent per person, Canada remains one of the three most polluting countries in the G20: with a carbon footprint of 19.4 tonnes per person in 2018, it is neck and neck with Australia (21.7 tonnes) and the United States (18.2 tonnes). This is more than double the average for G20 countries, which is 7.5 tons.

Quebec, meanwhile, is often presented as the “Canadian carbon footprint champion”, with its 10 tonnes of CO2 equivalent per capita. But how to calculate this figure is frequently questioned by experts. Indeed, the calculation only takes into account GHG emissions related to the production of goods in a given territory. If we add imports and exports, Quebec sees its carbon footprint climb to reach 15 tons per capita. In comparison, with this method of calculation, a country like France is at 10 tons per person.

To respect the Paris Agreement and keep global warming below 2°C, we should not exceed 2 tonnes per person on average. According to this calculation, Quebecers should therefore divide their current carbon footprint by 7.5 on average. -the-industry-to-reduce-its-carbon-footprint”>11. “ Efforts on an individual scale are derisory, it is up to the industry to reduce its carbon footprint ”

Yes, industry emits more GHGs than individuals. But individuals also have a share of responsibility for industrial emissions. A 2017 report by the Carbon Disclosure Project, an organization that measures the environmental impact of companies globally, attributed the emission of some 923 gigatonnes of CO2 equivalent to around 100 companies since the industrial revolution. However, 90% of this carbon was emitted not directly by these companies, but by their customers. “ It is the consumers who buy and burn the fossil fuels that these companies provide ”, explains in an interview for Vox the researcher at the head of this project, Richard Heede.

12. “ It is the very rich who pollute, with their yachts and their private jets ”

It is true that celebrities often make the headlines with climate-aberrant travel. According to a 2020 report by Oxfam, a group of NGOs fighting global poverty, the richest 1% on the planet are the people who pollute the most, with an individual carbon footprint that peaks at more than 70 tonnes of CO2 equivalent emitted each year.

However, according to this same report, this 1% contributes “only” 15% of planetary emissions. Taking no longer 1%, but the richest 10% of the planet, i.e. 630 million people, we reach 52% of total emissions, with an average of around 20 tonnes per person. These are people earning US$38,000 per year or more, again according to the Oxfam report, or just over C$52,000 per year at the current exchange rate.


CO2 which would be “ toxic”, the disappearance of species which would be “ minor ”… Where did those who doubt the reality of global warming go to find these arguments? It can be a well-meaning friend who would simply seek reassurance, or a malicious Youtuber who would like to deliberately mislead. Still, the only way to avoid falling into the trap of false information is to verify the source:

Where does the information transmitted by our friend or by this Youtuber come from?
Does the latter provide a link to an opinion piece, or to a real study conducted by recognized experts in the field?
Does the source of the information have a reputation for being reliable, or for peddling dubious news? Sometimes even Wikipedia can help us with this.

To go further on checking sources:

  • The episode “ Clues to Spot Fake News ” in Anatomy of Fake News
  • The Series Really True
  • The “ Journalistic sources ” educational sheet
  • The sheet 6 tips to avoid sharing misinformation

You should also remember that science is not built on the basis of debates of ideas, as in an electoral campaign, but on the basis of scientific studies. This means that after half a century of studying the causes and consequences of climate change, it is inevitable that statements as simple as “species will adapt to warming” or “species extinction will not no impact” have already been analyzed by experts: as a result, there is surely a solid literature to put these claims to the test. If in doubt, find out if an popularization site or a reliable media, in French or in English, would not have spoken about it.

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