Global warming: the battle of 2 ° C is almost lost
The United Nations is sounding the alarm about the insufficient efforts of the states to contain the rise in global temperature. After 2030, it will be too late. THE WORLD | 31.10.2017 By Pierre Le Hir
The climate battle is not lost yet, but it is very badly engaged. At this stage, there is a "catastrophic gap" between the commitments made by states to reduce their greenhouse gas emissions and the efforts needed to comply with the Paris agreement adopted at COP21, in December 2015 - at know how to contain the increase in the global temperature "significantly below 2 ° C compared to pre-industrial levels", trying to limit it to 1,5 ° C. This is the warning addressed to the UN Environment (former United Nations Environment Program), in a report published Tuesday 31 October.
This is not the first alert launched by the organization, which relies on a large international network of scientists. But it takes a particularly urgent tone, just days before the opening of the COP23 (6 November 17 in Bonn, Germany) and after a cataclysmic summer, during which a succession of hurricanes, floods and fires showed the vulnerability of rich and poor countries to climate change.
Mixed resultsCertainly, good news seems to be confirmed: annual global emissions of CO2 from the combustion of fossil resources (coal, oil and gas) and the cement industry, which represent 70% of total greenhouse gas emissions , have stabilized since 2014, at just under 36 billion tons (gigatonnes or Gt).
This is due to a lower growth in the use of coal in China but also in the United States - the two biggest polluters on the planet - and by the simultaneous expansion of renewable energy sources, starting with solar energy, particularly in China and China. in India.
However, the report notes, this stabilization has only been observed for a short period of time and the trend "could be reversed if the growth of the world economy accelerates". In addition, the picture is more mixed if one considers not only CO2 but also methane and all greenhouse gases, also produced by agriculture, land use changes and deforestation. Total emissions, of approximately 52 Gt CO2 equivalent in 2016, thus show a slight increase compared to previous years.
We are therefore very far from the drastic drop in emissions essential to achieve the objectives of the Paris Agreement. In order to contain the warming under 2 ° C, global releases to 42 Gt in 2030 should be capped, experts calculate. And aim for a maximum of 36 Gt to maintain a hope of staying below the 1,5 ° C bar.
Recent scientific studies - which the UN Environment indicates will be taken into account in future reports - even conclude that a much lower level of about 24 Gt in 2030 would actually have to be achieved in order to avoid climatic runaway.
A third of the wayHowever, the commitments made in 2015 by the 195 countries parties to the Paris Agreement, which 169 have ratified so far, will only achieve "approximately one third" of the way, warn the rapporteurs. Assuming that all states respect all their promises, sometimes conditional on obtaining international and, moreover, non-binding funding,
Earth is now moving towards a rise in the thermometer from 3 ° C to 3,2 ° C at the end of the century.Without additional effort, in 2030, humanity will have consumed 80% of its "carbon budget", that is to say the amount of CO2 that it can still release in the atmosphere without exceeding 2 ° C of warming. And she will have exhausted the entire budget allowing her not to go beyond 1,5 ° C.
In other words, "it is urgent to accelerate action in the short term and to strengthen national ambitions in the long term". The time is running out: "It is clear that if the gap [between necessary emission reductions and country commitments] is not filled by 2030 by then, it is extremely unlikely that the goal of maintaining the global warming well below 2 ° C can still be achieved, "insists the report.
"The situation is very worrying," said climatologist Jean Jouzel, former vice-chair of the scientific working group of the Intergovernmental Panel on Climate Change (IPCC). The first assessments of national policies show that overall, we are rather below the commitments made in Paris. And, without the United States, it will be very difficult to ask other countries to raise their ambition. In any case, he adds, "we remain very far from the account: to keep a chance to stay under the 2 ° C, it would be necessary for the peak emissions to be reached in 2020 at the latest. "
Hence the call of the United Nations to use the "facilitative dialogue" provided for by the Paris Agreement between the signatories in 2018, to revise upward the national contributions, which must be revised every five months. years. "Most G20 countries," says the report, "need new policies and actions to fulfill their commitments. It is also in the fall of 2018 that the IPCC is to issue a special report on the possibility or not of crossing the 1,5 ° C level, as well as on the consequences of a larger warming.
"Opportunities"UN Environment wants to remain optimistic. In his eyes, it is still "possible" to avoid widespread overheating. "A break in technology and investment can reduce emissions, while creating huge social, economic and environmental opportunities," says its director, Norwegian Erik Solheim.
The most radical solution is known: it consists of leaving underground between 80% and 90% of the coal reserves, half of those of gas and about one third of those of oil. This assumes, as a first priority, to no longer build new coal-fired power plants and to program the shutdown of nearly 6 700 units currently in service.
But, the rapporteurs continue, other levers must also be activated. By acting voluntarily in all economic sectors, it is 30 Gt 40 Gt per year that could be removed from the atmosphere.
On their own, the promotion of the solar and wind sectors, the improvement of energy efficiency, the development of alternative modes of transport, the cessation of deforestation and reforestation could bring down the annual emissions of 22 Gt. humanity has not yet burned all its cartridges. But she has entered the zone of all dangers.