How to limit climate change? What to remember from the latest UN expert report

The new report by the UN climate experts (IPCC), published this Monday, analyzes the reduction of emissions responsible for global warming, whose catastrophic effects are already being felt throughout the world.

Warming compared to the pre-industrial era already reaches 1.1°C, while the 2015 Paris Agreement sets the goal of keeping it well below 2°C and if possible 1.5°C.

These are the key points of this 2,800-page report, which represents the most up-to-date global scientific consensus on these issues.

Guarantee a peak of emissions in 2025

If greenhouse gas emissions are not significantly reduced by 2030, the 1.5°C target will be “out of reach”.

But current policies pave the way for 3.2°C of warming by the end of the century.

Meeting the +2°C target already seems extremely complicated: from 2030 to 2050 emissions would have to be reduced every year, as in 2020, an exceptional year in which a large part of the world economy was paralyzed due to Covid-19 . 19

In order not to exceed +2.5°C, emissions will need to peak in 2025, which seems unlikely as the trajectory has started to rise again from 2021, returning to pre-pandemic record levels .

However, at the level of emissions for 2019, the “carbon budget” available to maintain a 66% chance of staying below +1.5°C would be completely consumed in eight years.

Substitution of fossil fuels…

If all oil, gas and coal deposits currently in service are fully exploited without carbon capture technology, it will be impossible to maintain +1.5°C.

Removing fossil fuel subsidies could reduce emissions by 10%.

Maintaining +2°C means that 30% of oil reserves, 50% of gas reserves and 80% of coal reserves are not used, unless techniques for capturing and storing the CO2 emitted are developed.

The lost assets could amount to trillions of dollars.

…from low carbon or neutral sources

To meet the goals of the Paris Agreement, the world must achieve “carbon neutrality” in all respects by 2050.

PV and wind power capacity increased sharply, by 170% and 70% respectively between 2015 and 2019, thanks to falling costs, public policies and social pressure. But despite these spectacular increases, together they account for only 8% of global electricity production, 21% of low-carbon production.

In total, renewable and low-carbon energies – including nuclear and hydroelectric – account for 37% of global electricity production, the rest coming from fossil fuels.

reduce demand

The shift to less carbon-intensive energy must not overshadow structural transformations (soft mobility, electric vehicles, telecommuting, building insulation, fewer flights) that would reduce emissions by 40% to 70% by 2050.

“The profound and rapid changes in demand will facilitate the reduction of emissions in the short and medium term in all sectors”, the report points out.

Globally, the richest 10% of households account for up to 45% of total emissions.

Gag the methane

Emissions of methane, a greenhouse gas much shorter-lived than CO2 but 21 times more potent, contribute about a fifth of global warming.

Leakage from fossil fuel production (via wells or pipelines) accounted for about a third of these emissions in 2019. Animal husbandry is also a major source.

Complying with the Paris Agreement means halving methane emissions by 2050 (compared to 2019 levels).

CO2 capture

Even in the best scenarios, emission reductions will have to be accompanied by the implementation of carbon dioxide removal (CDE) techniques, or “negative emissions”, to achieve carbon neutrality.

The possibilities range from the natural capture of CO2, by planting trees for example, to the extraction of CO2 from the atmosphere, a technology not yet developed.

Ces EDC devraient permettre de compensate les émissions de secteurs que ne pourront pas suffisamment réduire leurs émissions d’ici à 2050 – aviation, maritime transport or cimenteries – et seront également nécessaires pour hope rétablir la situation en cas de dépassement des objectifs de l’Accord from Paris.

Acting is expensive…

Reaching the +1.5°C goal will require investments of 2.3 billion dollars per year between 2023 and 2052, just for the electricity sector. The figure drops to 1.7 trillion for +2°C.

In 2021, $750 billion was spent worldwide on clean energy or energy efficiency, according to the International Energy Agency.

According to the IPCC, rich countries spend two to five times less than necessary and investments in developing countries are four to eight times less than necessary.

Maintaining the +2°C target would see global GDP fall from 1.3% to 2.7%, compared to the current trajectory, and fall from 2.6% to 4.2% to maintain +1, 5°C

… do nothing else

However, these estimates of (de)growth do not take into account the foreseeable gains, the consequences of avoiding climate catastrophes, food crises or the collapse of ecosystems.

“The benefits of scenarios to limit warming to 2°C outweigh the costs of (emissions) mitigation measures throughout the 21st century.” the report points out.

The only benefits in terms of public health derived from a reduction in air pollution – the cause of 7 million premature deaths a year throughout the world – would, for example, be of the same order as the investments to achieve this objective.

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