For all the ambiguity of her figure, Greta Thunberg made a great contribution to the popularization of the topic of climate change and once again marked the abyss of misunderstanding between scientists and everyone else. Scientists have long answered positively the questions of whether there is warming and whether humans are to blame, but society still reflects and cannot accept this point of view. Business and politicians understand that to accept means to act, incur losses, make unpopular decisions. Moreover, the big oil business even finances various activities and studies to disinform climate science. The layman has his own problems – he needs to feed his family, and he is suddenly blamed for global problems. Society does not want to feel guilty. And he is looking for ways to retreat: what if the scientists are wrong? And as if grasping at straws for different versions: some “experts” say that the person is not to blame, and some – that there is no warming. And that, they say, in general, this whole story with global climate change is a complete fiction, a fake.
Myth one: “How many experts, so many opinions”
There are several characteristic myths and misconceptions about climate change that wander from year to year, from decade to decade. Many small myths are based on the principle “How many experts, so many opinions.” How to figure out who to trust? One doctor of sciences (Alexander Gorodnitsky – The Insider) says that we are waiting for a cold snap, another, also a doctor of sciences, that warming. And which of them to believe? But the first one is also a bard to boot, that decides the matter! But does it decide? Imagine you came to two doctors who prescribe different drugs. For one, “it helps my patients, I tell you this as an expert with 30 years of experience,” for the second: “the effectiveness of this drug has been proven on the basis of a double-blind, placebo-controlled test on a large sample.” What to choose? It is obvious that one should look at the argumentation of one or another expert.
So what is the argumentation of the vast majority of climate scientists in favor of the anthropogenic cause of modern warming? At the same time, I would not like to operate with the words “consensus” and “97%”, because this is not evidence in itself. The argument is based on the following main points. There is a rapid increase in the concentration of carbon dioxide (and methane) in the atmosphere. This growth is confidently attributed to human activity (with the burning of fossil fuels): on the one hand, based on the analysis of the carbon cycle, that is, estimates of the carbon content in different elements of the climate system (atmosphere, ocean, biosphere) and flows between them, on the other hand, on basis of carbon isotopic analysis.
The increase in carbon dioxide concentration is confidently attributed to human activity.
An increase in the concentration of carbon dioxide leads to an increase in downward long-wave radiation (an increase in the greenhouse effect), as was assumed more than a hundred years ago, and has recently been proven experimentally. Additional heat entering the climate system warms up the lower layers of the atmosphere and the upper layer of the ocean, leads to the melting of ice and an increase in the level of the ocean, while the upper layers of the atmosphere do not receive this heat, which leads to a decrease in temperature in the stratosphere and mesosphere – all this is reliably detected. Numerical models of the earth system (climate models) do not reproduce the current warming when only natural factors of climate variability (solar and volcanic activity) are taken into account, and they reproduce if the anthropogenic impact is taken into account.
Myth #2: “They can’t predict the weather”
And here the second myth enters the scene: “Yes, I don’t believe in these models, they cannot predict the weather for the day.” Indeed, people often confuse weather and climate models. Both are based on the equations of hydrodynamics, radiative transfer, and chemical transformations. But there is one important difference: weather models must remember the initial conditions, and the noise in the initial conditions in such a chaotic system as the atmosphere quickly begins to prevail over the signal. Already after 10–14 days, weather models “forget” about the initial conditions – here lies the limit of weather predictability in the form we are used to. But for the first days (up to 3–5 days), models now predict the weather very successfully.
Over the past decades, there has been a real quiet revolution in weather forecasting, primarily associated with the four-dimensional assimilation of satellite information and the ensemble approach. The myth that “forecasters lie all the time” is very tenacious and is connected with psychology: with a 24-hour forecast accuracy of 97.5%, ordinary people more often remember those same 2.5% of unsuccessful forecasts.
Weather forecasts for 24 hours come true in 97.5% of cases
And what about the climate? Here the word “forecast” will not be correct, rather they are talking about climate projections. Climate models do not immediately remember the initial conditions, only boundary conditions are important for them – that is, external influences: solar activity, volcanic eruptions, anthropogenic activity. How is anthropogenic activity defined? Economists are preparing their own models of the development of society: how many people will live there, how industry will work, how energy, land use will develop, etc. All this is formalized into some parameters that can be assimilated by the climate model – for example, in the emission of CO2 and in the change in surface properties.
Solar physics experts present their forecasts for the development of solar activity – whether we are waiting for the continuation of the 11-year cycle, or some kind of minimum is expected. Volcanologists should ideally present their forecasts for volcanic eruptions, which are an important factor in climate, but here the predictability is very weak. Based on all the new external parameters, climate models calculate a new climate – that is, a certain statistical ensemble of various weather conditions that are characteristic of this new climate. But not specific weather in a specific place on a specific day. Only a certain ensemble, by which one can judge how the distribution of a value, its average, extremes, etc., will change.
Myth three: “The summer was cold, what kind of warming are we talking about?”
The next myth also stems from the mixing of weather and climate. It varies from: “I don’t feel warming on myself” to “What a cold summer it was, what kind of warming are we talking about?”. In both cases, we are talking about the weather. The more the weather changes from season to season, the harder it is against the background of this rattling for the layman (who is unlikely to keep a weather diary) to trace some trend. Just focus on the sensations, and they can sometimes fail.
Myth #4: “Man is so small, how can he influence the global climate?”
The problem of scale underlies another climate myth – about our smallness and insignificance, which varies from the philistine “Man is so small, how can he influence the global climate?” and “Yes, more CO2 comes from volcanoes than from all human activity” to the more scientific “CO2 fluxes from anthropogenic activities are small compared to natural ones” and “The main greenhouse gas is water vapor.” But here, as in the proverbs “small spool, but expensive” and “a drop of nicotine kills a horse”, a small amount is not at all equal to a small effect. Anthropogenic carbon fluxes are about 10 gigatonnes of carbon per year, which is about 100 times greater than the flux from all volcanoes, but indeed significantly less than the total carbon fluxes between the atmosphere and the biosphere (about 120 GTC/year), atmosphere and ocean (about 80 gtc/year). However, the fact is that natural flows are balanced, while anthropogenic ones (despite their smallness) are not. As a result, carbon dioxide accumulates in the atmosphere, which, being a greenhouse gas (indeed, the second after water vapor), begins to actively influence the radiation balance of the Earth’s surface, bringing an additional 2 W/m2. These additional watts lead to the accumulation of heat in the climate system and an increase in temperature.
On the other hand, the temperature is rising, so what? “The climate has been changing all the time, and there have been warmer periods.” This frequent statement is not entirely a myth. Indeed, the Earth’s climate has gone through different periods – both much colder than now, and much warmer. This only demonstrates the sensitivity of the climate to changes in the heat balance of the system. It is misleading to compare “head-on” past and present climate change. When analyzing these changes, it is important to evaluate not how the temperature changed, but why it changed.