The latest IPCC report reiterates that the planet is heading towards an unprecedented catastrophe, but also lists the solutions with which it is possible to avoid it.

An instruction manual to use immediately

Audrey Garric, Le Monde, France

We are on the brink of the abyss. Human activities are altering the climate at a rate unprecedented for thousands of years, with catastrophic and often irreversible effects.

The lives of billions of people are already affected, and continuing to emit greenhouse gases will exacerbate risks to food production, water supplies, human health, national economies, and the survival of much of the natural world.

But humanity can still take a step back, provided that emissions are drastically reduced in every sector. The solutions are many and can be implemented immediately.

The Intergovernmental Panel on Climate Change (IPCC), which published a summary of eight years of work on 20 March, still nurtures a faint hope that it will be possible to limit global warming to 1.5 degrees more than in the pre-industrial period, provided of an international outcry.

“The climate time bomb continues to count down, but this report represents a practical guide to defuse it, a manual for the survival of humanity,” said UN Secretary-General António Guterres.

The document, written by 93 scientists, is the most comprehensive summary of the climate science that should guide world political action.

In it, the IPCC summarized the three sections of its assessment report (published between 2021 and 2022 and devoted to the physical basis of warming, its effects, and solutions) and the three special reports that addressed the consequences of global warming 1.5 degrees, land and ocean, and cryosphere effects, closing a process started in 2015.

Although it contains already known considerations, the summary and its summary for policymakers were agreed upon by representatives of the 195 countries making part of the IPCC only at the end of a long week of discussions in Interlaken, Switzerland.

As always, the thirty pages were negotiated line by line with the authors. The document reiterates it categorically: human activities have “unequivocally” caused global warming.

Between 2001 and 2021, the average temperature was about 1.1 degrees warmer than in the period 1850-1900. Human activities, especially the use of fossil fuels and deforestation, produce greenhouse gas emissions that increase every year.

In 2019, they reached 59 billion tons. Emissions vary from one country to another but largely depend on the level of wealth.

The concentration of greenhouse gases in the atmosphere has reached levels not seen for two million years for carbon dioxide and for eight hundred thousand years for methane.

Extreme climatic phenomena (heat waves, droughts, floods) have become more frequent and intense. The melting of glaciers and the rise of sea levels are accelerating.

Today almost half of the human population (between 3.3 and 3.6 billion people) lives in “places that are very vulnerable to climate change”. Millions of people are exposed to acute food insecurity.

About half of the world’s population experiences severe water shortages for at least part of the year. Extreme events have caused an increase in mortality and favored migration and the spread of diseases.

The poorest communities are also the hardest hit because they have fewer tools to deal with the emergency, as the damage caused by Cyclone Freddy in Malawi recently demonstrated. Also, sufferings are animal and plant species, victims of episodes of mass mortality.

Insufficient progress

There are far more laws and measures to reduce emissions today than in 2014 when the last IPCC summary report was released, but they often fall short of the problem.

In the last decade, only eighteen countries have managed to reduce emissions. And the trend is worrying. If the commitments made are respected, the planet will go towards a warming of 2.5 degrees by the end of the century.

If, on the other hand, current policies continue, the temperature will increase by 2.8 degrees. The IPCC notes some progress in adapting to climate change, but even this remains insufficient, especially in low-income countries that do not have access to the necessary technologies and finances.

“The majority of adaptation measures are piecemeal, progressive, sectoral, and unevenly distributed across different regions,” reads the report, which also highlights the increase in “bad adaptation”.

This is the case with the construction of coastal dikes, which protect people and property but exacerbate erosion and damage natural ecosystems.

The report indicates that some limits to adaptation have already been crossed or are on the verge of being crossed.

Small island dwellers, for example, can no longer manage rising waters unless they overcome a series of financial, political, and technological problems. A part of ecosystems – coral reefs, tropical forests, polar regions – has now reached a point of no return.

The worst is yet to come, but there is still time to curb the disaster.

In the short term (2021-2040) the warming will continue in any case, and the 1.5 °C threshold is expected to be exceeded at the beginning of the next decade.

But our current actions will determine the size of the long-term climate imbalance. If emissions were cut sharply, global temperature could rise by 1.4 degrees between 2081 and 2100, which would rise to 2.7 degrees in the intermediate scenario and 4.4 degrees in the worst-case scenario.

Although many scientists give up on the 1.5-degree goal, climatologist Valérie Masson-Delmotte, co-chair of IPCC Group 1, still believes that the target makes sense: “The next step will be to keep warming as much as possible. close to 1.5 degrees”.

As the IPCC keeps reiterating, every fraction of a degree matters enormously and results in more intense and frequent extreme weather events.

Continued emissions will cause more severe disruptions to the water cycle, accelerated melting of glaciers, worsened ocean acidification and de-oxygenation, decreased agricultural production, and reduced efficiency of carbon sinks such as forests and oceans, which currently absorb half of the emissions.

Some changes are irreversible. The rise in sea levels, for example, will continue for centuries or millennia under the effect of warming water and the melting of the polar ice caps.

According to the various scenarios, by 2100 the level of the oceans could rise by between a foot and a meter. The IPCC underlines the risk of crossing tipping points such as the destabilization of the Antarctic ice cap.

“The choices we make in this decade will determine our future, but they will also have millennial consequences,” explains Valérie Masson-Delmotte.

The last glimmer

The window to avoid the worst effects of the climate crisis “is closing rapidly”, but according to the IPCC, we can still exploit it.

To stay within 1.5 degrees, net carbon dioxide emissions would need to fall 48 percent from 2019 levels by 2030, before falling to zero in the early 1950s.

To stay below two degrees, the drop would have to be 22 percent, with the net zeroing in the early seventies. In any case, the maximum peak will have to be reached “at the latest” in 2025.

How to do it? First of all, we need to “substantially” reduce the use of fossil fuels, especially in the absence of technologies for the sequestration and storage of carbon dioxide (CCS).

“The already active fossil infrastructure consumes the entire carbon budget for 1.5 degrees,” Masson-Delmotte points out.

It is necessary to close the plants earlier than expected and accelerate the use of low-emission energy, starting with photovoltaic and wind power, which are already very accessible.

Techniques for removing carbon dioxide from the atmosphere (Cdr), especially afforestation, are defined as essential to limit warming to 1.5 degrees and to return below this threshold after exceeding it, but their use on a large scale raises “problems of feasibility” and “social and environmental risks”, especially with regard to land use.

The report lists the possible solutions in detail: rethinking cities, managing crops in a more sustainable way, changing the power supply, and developing electric cars.

Protecting 30-50 percent of land, freshwater, and oceans would help keep the planet healthy. Adopting these solutions quickly would reduce the damage of global warming and bring health and economic benefits.

The report highlights the importance of increasing funds for the climate, which are insufficient, especially in developing economies, and of introducing fair and equitable policies.

All countries must “push on the accelerator immediately”, summarized António Guterres, who asked the richest ones to bring forward the zeroing of net emissions to 2040.

The UN secretary wants governments to revise their commitments upwards in view of the United Nations world climate conference (Cop28) which will open in November in Dubai.

On that occasion, a first assessment of individual countries’ efforts will be drawn up after the 2015 Paris Agreement.

The assessment will also be based on the IPCC report. “Every state must be part of the solution,” Guterres concluded. “If others are expected to act first, humanity will come last.”