IPCC's latest climate report says to limit global warming to 1.5°C
World must cut carbon emissions by 40% by 2030
Limiting global warming to 1.5°C is the most ambitious goal of the Paris Agreement, according to the latest report "Climate Change 2022: Mitigating Climate Change" released by the United Nations Intergovernmental Panel on Climate Change (IPCC) on April 4, in order to achieve The target, unless global greenhouse gas emissions peak by 2025 and fall by 43% by 2030, the world could suffer from extreme climate impacts.
However, at current levels of rising temperatures, greenhouse gas emissions could cause twice the level of global warming: about 3.2°C by 2100.
Greenhouse gases in Earth's atmosphere are at the highest levels in human history.
Greenhouse gas emissions fell sharply in 2020 due to the lockdowns brought on by the pandemic, but in 2021 they equaled or even surpassed the 2019 record.
Emissions in 2019 were about 12 percent higher than in 2010 and 54 percent higher than in 1990.
This report is the third and final part of the IPCC's Sixth Assessment Report.
It sends a stark message to the world: Achieving the climate goals of the Paris Agreement is still technically feasible, but an immediate, rapid and concerted international effort is required to radically transform the home we all depend on.
"If we want to limit global warming to 1.5°C, there is no time to lose," said Jim Skya, co-chair of IPCC Working Group III. It's impossible."
In fact, the report is not entirely pessimistic.
Despite rising emissions, there are signs that some mitigation measures are already working.
"We are at a crossroads. The decisions we make now can ensure a livable future. We have the tools and technologies we need to limit warming," IPCC Chairman Lee Hui-sung told a news conference.
Two technologies help reduce CO2 emissions
The report notes that for countries to achieve their net-zero emissions targets, it is not enough to reduce emissions, but also to extract carbon dioxide (CO2) from the atmosphere.
This will offset remaining greenhouse gas emissions from sectors such as industry and aviation.
Countries can promote carbon sequestration by expanding forest areas and improving agricultural practices, or through a variety of emerging technologies that capture carbon emissions from industrial sources or directly from the atmosphere.
The report concludes that to have a two-thirds chance of keeping global temperature rise below 2°C, climate models predict that between now and 2100, we will need to employ one or two emerging technologies to absorb 170 billion to 100 million pounds from the atmosphere. 900 billion tons of CO2.
In the first method, called Bioenergy Carbon Capture and Storage (BECCS), CO2 from the combustion of power plants is captured in smokestacks and buried in the ground, thereby removing CO2 from the atmosphere.
In the second technique, known as direct air capture (DAC), machines absorb CO2 from the air through a chemical reaction.
The report also suggests that both approaches are flawed.
The first method requires large amounts of water and can negatively impact biodiversity.
The second approach may increase emissions in other areas of production.
Deep, fast cuts to methane emissions are critical
Although methane has a shorter lifetime and is less abundant in the atmosphere than CO2, methane is a more powerful greenhouse gas.
Methane is projected to account for 60 percent of non-CO2 greenhouse gas emissions by mid-century.
However, because it is less persistent in the atmosphere, slashing methane emissions could quickly reduce its warming impact.
One of the most effective ways to do this is to target "fugitive" emissions -- the methane that escapes into the atmosphere during natural gas extraction and transportation, or from long-abandoned oil wells.
According to IPCC calculations, fugitive methane accounts for about 32% of the global methane emitted to the atmosphere and 6% of all greenhouse gas emissions.
All industries need to reduce emissions, and countries should seek to move away from fossil fuels, including the industry and transport sectors, the IPCC report said.
Clean energy is a "potential stock" for emission reduction
To limit global warming to 1.5°C, coal use must be cut by 95% globally, while oil and gas consumption must be reduced by 60% and 45%, respectively, by 2050.
Fortunately for many places, installing new clean energy is cheaper than operating existing fossil fuel energy sources, and often cheaper than installing new fossil fuel infrastructure.
From 2010 to 2019, the cost of solar and lithium-ion batteries fell by an average of 85%, while the cost of wind energy fell by 55%.
This decline has allowed these technologies to be more widely deployed.
For example, the use of electric vehicles has soared by a factor of 100 in this decade, and the penetration of solar energy has increased by a factor of 10 worldwide, although these figures vary by country and region.
“We already have all the technologies we need to decarbonize our economy, at least at the research, development and demonstration stage, and those we still need to develop can be developed quickly with the right policies.” Founding of End Climate Silence Genevieve Genser said, "If we do it with our heart, we can do miracles."
The situation is urgent but not hopeless
Despite the urgency of the report's conclusions, Alexander Barron, an assistant professor of environmental science and policy at Smith College in Massachusetts, said, don't assume the battle is largely lost if greenhouse gas emissions continue to rise beyond 2025. .
“Even if the temperature rises above 1.5°C, as long as we keep it below 2°C, every tenth of a degree in between will greatly reduce human suffering. We really need to accelerate everything on all fronts, we wait The longer it is, the more climate damage it will cause.”
"The biggest uncertainty in the IPCC report is what people will do, which is out of our control. We can choose one path or the other. The question is how many people will fight for it," Barron said.
Intern reporter Zhang Jiaxin