Swedish 16-year-old environmental activist Greta Thunberg addressed the UN Climate Summit in New York in September. We asked a climate scientist to dissect all her ideas related to ecology – where she’s right and where she’s wrong.
The full transcript of Thunberg’s speech is available here.
As an introduction I would like to note, that the whole speech is purposefully charged with emotions: it’s normal for an activist – environmental, climate, economic, etc. (otherwise no one will hear him). That’s why we’ll analyze only facts, not touching upon the emotional side.
Thesis 1. Humanity is on the verge of mass disappearance.
Taking into account that modern climate disasters (heat waves, massive rainfalls causing floods) during the last 10-20 years consistently lead to deaths in countries with different living standards (up to 50 000 only in the European Russia in 2010), and modern scientific data show that such events are becoming more often, Greta exaggerates here, but not out of nothing.
Thesis 2. If temperatures rise more than by 1.5 degrees Celsius, irreversible and uncontrollable chain reactions will be launched.
Complex calculations by many scientific centers around the world summarized by the IPCC show that
“Limiting global warming to 1.5°C compared with 2°C would reduce challenging impacts on ecosystems, human health and well-being”.
The magic number “1.5 °C” is the safest and theoretically achievable warming level (for instance, we can’t limit it to 1.0°C anymore) with which the civilization stays sustainable and which it can contend.
Scientists are sure that a 1.5°C warming will make certain species (like plankton and fish) move to higher latitudes. But seaweed and coral reefs have less abilities to move and, according to forecasts, up to 90% of coral reefs in tropical latitudes will disappear. Practically all of them (> 99%) will be lost in case of a 2°C warming. It will happen due to ocean acidification and death of photosynthetic organisms living in corals.
Thesis 3. With the current emissions level the rest of the CO2 limit will be fully used in less than 8.5 years.
More precisely, we have about 10 years to confine to the “1.5 °C” scenario. Calculations show that for that we have to reduce CO2 emissions caused by human activities almost by 45% by 2030 compared to 2010 and reach a “clean zero” by around 2050. It means we have to cut now (and we know that 10 years is not a term for process optimization).
Thesis 4. World leaders and large companies stand still.
And here Greta is probably right world-wide: real steps to cut emissions are only taken in Europe (and not everywhere) and some other countries. It’s obviously not enough to cut them to the “1.5 °C warming” level and probably not enough to stop the temperature rise at a “+ 2 °C” level by 2100. There is much less done in the world to promote real change and it bothers experts a lot.
To sum it up, if we don’t discuss emotions, Greta’s arguments are based on the main modern document, an almanac of contemporary knowledge on the climate change process – the IPCC (Intergovernmental Panel of Climate Change) report. Thus Greta is in fact the main PR person for the scientific approach to the problem and everything she claims corresponds to the recent scientific data on the problem.
By the way, the IPCC report is available in 6 languages.