Key figure: +1.5° C

The last IPCC report  (Intergovernmental Panel on Climate Change), published on 9 August 2021, had a major impact since for the first time it “unequivocally” emphasised the role played by human activities in global warming

A 1.5 °C rise in temperature is probable by 2030

 

Another observation also demands our attention: the emergency of the situation. It is not only a question of what type of planet we’ll leave to future generations but that of the planet on which we will spend the next ten years of our lives.  In every scenario considered by the experts, the Earth will warm by at least +1.5° C from now to 2030 in comparison to the preindustrial era. The other scenarios are more pessimistic but not implausible, as they predict an increase of the Earth’s surface of +3.3° C and even +5.7° C. If they are complied with, the commitments made in the framework of the Paris Agreement will currently lead to a world of +3° C by 2100. Far from the target of 1.5° C announced.

 

Considerable impacts on the water cycle

 

The impact of such ominous predictions of warming becoming reality will exacerbate problems linked to water and be at the heart of environmental news in the coming years. The authors of the report dedicate nearly 200 pages to the water cycle.

The acceleration of the water cycle corresponds to greater evaporation of water into the atmosphere due to the strong heat caused by climate change. However, as the rate of humidity in the atmosphere reaches its maximum, the atmosphere has to “evacuate” this excess humidity in the form of higher rainfall. Indeed, an increase of extreme daily rainfall of 7% per degree increase of global temperature has been observed. Precipitations will therefore become more intense at higher latitudes and in certain equatorial regions, with more severe floods due to soil erosion.

To sum up, we will see an aggravation of two extremes: dry climate regimes will become more likely to include long and severe droughts whereas humid regimes will be subjected to more extreme precipitations, as was seen in China in July 2021.

 

People’s daily lives are greatly disturbed

 

The impacts of such extreme meteorological events jeopardise the resources of many populations who depend on them for their subsistence.

The issue of glacier melting is especially problematic in this regard. Early flows and increased discharges in winter are already disturbing the living conditions of hundreds of millions of people living downstream who depend on ice-melt for their drinking water and agriculture (whether the water comes from rain or from irrigation, variability is a major problem). The danger here is that of worsening food security for entire populations. The energy security of the same populations is also threatened, with more variable discharges affecting hydroelectricity production. Then there are the direct effects of glacier melting, such as landslides and avalanches, inevitably followed by drought, thus affecting people’s physical safety.

Another direct consequence of glacier melting is rising ocean and sea levels, which are already affecting certain islands and coastal cities: this rise could reach +2 meters from now to 2300. This phenomenon is already well underway: the rise observed since 1900 is + 20 cm, and a rise of one meter is foreseen by 2100. According to the authors, this rise will be irreversible for hundreds and even thousands of years.

Around the world, these changes affecting hydric systems are already aggravating situations of extreme poverty, and the burden risks becoming greater for women, traditionally responsible for supplying water to their families. The reduction of available water resources and discontinuous access to them increase the exposure of populations already in difficulty.

 

Beyond the figures

 

Beyond the figures, the report’s central message is the very concrete temporal and geographical reality of the climate change described. Discourses should no longer call for the need to act for future generations but focus on preserving our own lives now, everywhere on the planet. The effects can already be seen: this summer of 2021 on Earth, droughts and forest fires occurred hand in hand with floods and landslides.

 

The urgent need to act

 

What can be done in the face of this disturbingly violent reality? There is a clear relation between greenhouse gas emissions – higher temperatures of the Earth’s surface – and the disruption of the water cycle. Each fraction of a degree avoided by reduced emissions counts. Governments must therefore be ambitious with their national plans to reduce greenhouse gas emissions, while ensuring that emissions avoided on national territory are “exported” to countries that have fewer resources to reduce such emissions. It is imperative to take “imported” emissions into account.

Coordinated action taken urgently on the scale of the planet may avoid the tipping points of the global climate: these tipping points are thresholds beyond which changes could become irreversible. The message expressed by scientists in this report is clear: the situation is extremely alarming, but we are not condemned. Every action counts.