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ne point five to stay alive. That’s the famous slogan that was first adopted by a group representing the small island developing states of the Caribbean and later adopted by young climate activists, NGOs, and politicians around the world.
It is a message that conveys, for some, that limiting the rise in global temperature to 1.5 ° C above pre-industrial levels by the end of the century, the most optimistic goal of the Paris Agreement, is seen as the only acceptable outcome for our planet. This is a view that is often shared by people in developing countries, who have done the least to provoke the climate crisis and yet stand to lose the most from its impacts.
Writing in The independent , prominent Ugandan climate activist Vanessa Nakate says: “I was driven to act by what I was witnessing around me: people in my country losing their homes, their income and their lives due to extreme weather … I can tell you, a 2C A warmer world is a death sentence for countries like mine ”.
Five years ago this week, nearly every country in the world pledged to limit global warming to “well below” 2 ° C above pre-industrial levels and to strive to keep temperatures at 1.5 ° C by the end of century as part of the historic climate of Paris. Agreement.
A landmark report published in 2018 exposed how different the world could look with 1.5 ° C of global warming versus 2 ° C, the upper limit of global temperatures agreed by countries under the Paris agreement.
The report, produced by the Intergovernmental Panel on Climate Change (IPCC), a leading independent group of climate scientists, found that limiting warming to 1.5 ° C instead of 2 ° C could prevent more than 10 million people from suffering. the impacts of sea level rise, largely in such a way as to further increase to extremes of heat and prevent tropical coral reefs from disappearing altogether.
However, today, global average temperatures are already around 1.2 ° C above pre-industrial levels. And the current policies of world leaders would put us on the road to warming around 3 ° C by the end of the century.
“For a long time we’ve had this glaring disconnect between the goals of the Paris Agreement and the commitments made by countries,” said Dr. Zeke Hausfather, climate scientist and director of climate and energy at the Breakthrough Institute, a group of environmental experts. in California. , saying The independent.
Last week’s analysis by Dr. Hausfather for the climate website Carbon Brief found that, based on projections from the latest models, the world could exceed 1.5 ° C between 2026 and 2042 if little is done to address emissions, and between 2026 and 2057 if strict measures are taken. they are taken to meet the objectives of the Paris Agreement.
“If we were to give a better estimate of when the latest models think we will go above 1.5 ° C, it will probably be around 2032,” he said.
However, very recent moves by the leaders of major economies around the world allow some room for optimism, he added.
In the summer of 2019, then-UK Prime Minister Theresa May promised that the country would achieve net zero emissions by 2050. Similar commitments from the EU, Japan and South Korea this year.
China, the world’s largest emitter, shocked the world in October when it also announced its intentions to achieve “carbon neutrality,” somewhat later than 2060. And in November, President-elect Joe Biden promised to commit states United, the second issuer, to net zero emissions by 2050 when he enters the White House.
President-elect Joe Biden speaks during an event at the Queen Theater in Wilmington, Delaware, Tuesday, Dec. 8, 2020, to announce his healthcare team
(AP)
A recent quick analysis by Climate Action Tracker (CAT), an independent research group, found that if all these new net zero promises are fulfilled by 2050, it could keep global average temperatures in 2100 as low as 2.1 ° C above. from pre-industrial conditions. levels.
Professor Niklas Höhne, a climate scientist and founding partner of the NewClimate Institute in Germany who conducted the analysis for CAT, said The independent: “Climate Action Tracker has analyzed the temperature impact of what countries are doing for 10 years.
“Usually it’s a bit frustrating because not much has changed in the past, we were basically always going in the direction of 3 ° C of warming at the end of the century. Now we have seen a significant change for the first time and that is because more and more countries are taking seriously the idea of reaching net zero. ”
However, it is worth noting that this new 2.1C result depends on countries quickly turning their net zero promises into action, he added.
“The second and even more difficult step is to enact short-term policies to guide countries toward meeting their long-term goals,” he said. “And there, sadly, we have to say that no country has policies in place to put them on the path to a net zero goal.”
In recent days, both the UK and the EU have made new short-term promises to increase the rate at which they will cut emissions by 2030. However, the policies needed to achieve these more ambitious goals have yet to emerge.
“These short-term promises are absolutely essential,” said Dr Joeri Rogelj, director of research and lecturer on climate change and the environment at the Grantham Institute at Imperial College London. The independent.
“First of all, emissions are not reduced from the current level in a single year, a long-term path is needed. Having deep and early cuts reduces the maximum amount of warm-up we have to deal with. “
US Secretary of State John Kerry holds up his two-year-old granddaughter for the signing of the agreement at the United Nations signing ceremony for the Paris agreement on climate change.
(Fake images)
Climate Action Tracker’s analysis returned a central estimate of 2.1 ° C, but it is worth noting that there is still uncertainty around this figure, Professor Höhne said.
“When we published these temperature estimates, we said 2.1 ° C, but the full range for the estimate is 1.7 to 2.7 ° C. That is something we must not forget. It could be a lot worse, but it could also be better. ”
The range in the estimates is related to the uncertainty about how the climate system will react to much higher levels of greenhouse gas emissions in the atmosphere.
Climate scientists have spent years trying to understand how “sensitive” Earth’s climate could be to much higher levels of CO2. To do this, researchers have been trying to figure out how much the world will warm in response to a doubling of CO2 levels in the atmosphere, compared to pre-industrial times. This estimate is known as “climate sensitivity”.
Research suggests that climate sensitivity is between 1.5 ° C and 4.5 ° C.
If it’s at the low end, the temperature rise at the end of the century could be less than 2.1 ° C, said Professor Höhne. If you’re on the higher end, the heating could be more severe.
However, neither end of the range would see current net-zero promises keep temperatures at 1.5 ° C. For this to happen, more countries would need to commit to reaching net-zero emissions, Professor Höhne said.
He said: “So 127 countries now have net zero targets and cover two-thirds of greenhouse gas emissions. But it means a third is still missing.
“That other third would have to go in and reduce their emissions in the same way. But I think that now that we have a critical mass, I am no longer so worried about this other third because they will have to join if they want to trade with other countries. ”
The real challenge for 1.5C remains to get all countries to increase their ambition in the short term, he added.
Reducing emissions at the rate necessary to reach net zero by 2050 will not be an easy task for any country, said Dr. Hausfather: “We are not just talking about building a lot of wind and solar power, we are talking about decarbonizing every sector. . of the economy: agriculture, industry, transport, aviation “.
The IPCC’s landmark 1.5 ° C report examined possible pathways the world could take to limit global warming to 1.5 ° C by the end of the century. Although some pathways predict that the world will reach 1.5 ° C through emissions cuts alone, many suggest that the use of “negative emissions technologies”, techniques to remove CO2 from the atmosphere, may be necessary to absorb some of it. of our pollution.
The range of negative emissions technologies currently available varies in their level of development, scalability, and potential side effects.
Many 1.5C scenarios include the use of a technology called Bioenergy with Carbon Capture and Storage (BECCS). Simply put, this technology would involve growing crops to absorb CO2 from the atmosphere, burning these crops to produce bioenergy, and then capturing the resulting emissions from the air to store on land or under the sea.
BECCS has been piloted but not yet developed on a large scale. Using BECCS alone to keep global warming at 1.5 ° C would require the use of large amounts of land for growing bioenergy crops, competing with the space needed for wildlife and food production.
“We are really talking about potentially planetary-scale engineering here to really meet that goal,” Dr. Hausfather said.
A thousand mayors from different cities gather at the Paris city hall during the COP21 Climate Conference in Paris
(Fake images)
Other commonly proposed negative emission techniques, such as tree planting, would also take up space. And some, like “direct air capture,” the idea of using machines to suck CO2 directly out of the air, is still far from a commercial reality.
However, if a variety of different negative emissions techniques were implemented along with strict emissions cuts, we could give ourselves a fair chance to limit global warming, said Dr. Rogelj.
“While the IPCC special report on land highlighted these important risks and trade-offs [for negative emissions], also shows that if you implement best practices, these tradeoffs can be avoided. ”
However, even if efforts to reduce emissions are intensified and negative emissions technologies are developed at scale, it still would not guarantee that global warming remains at 1.5 ° C, he added.
“I think for 1.5 ° C, we have to be lucky somehow. Even if we go down that very steep path towards the middle of the century, that gives us 50 percent of that we end up at 1.5 ° C. We do exactly what we need to do and we could still end up with further warming. ”
However, it is important to understand that 1.5 ° C and 2 ° C are social targets, rather than key trigger points in the Earth system, he added. That means that while crossing the 1.5 ° C limit is not desirable, it will not lead to sudden and uncontrolled climate change, and all actions taken to limit global warming will still be important.
“At the end of the day, the weather is more a matter of degrees than thresholds,” added Dr. Hausfather. “It would be great to limit global warming to 1.5 ° C, but if we end up at 1.6 or 1.7 ° C, the world doesn’t end.
“It is a useful objective to have to guide the ambition of the countries, but at the same time it is a political construction.”
