The latest UNEP report highlights the urgent need to change the current direction to meet the objectives of the Paris Agreement. Despite some advances in climate policies and low-carbon energy, the world is heading toward a warming of 2.7°C for 2100. In addition, it is dangerously close to the limit of 1.5°C of the Paris Agreement. La COP28 in Dubai will be crucial, and the report stresses that achieving temperature objectives depends on strengthening mitigation measures in this decade and closing the emissions gap.
Despite falling clean energy costs and more ambitious climate policies in some countries, global greenhouse gas emissions increased by 1.2% from 2021 to 2022, reaching a record of 57.4 gigatonnes of carbon dioxide equivalent (GtCO2e). This increase, which reverses the decline during the pandemic, is mainly due to CO2 from fossil fuels, responsible for two-thirds of emissions. The report also highlights that global investments in fossil fuel extraction have grown, and governments plan to more than double the production of fossil fuels by 2030 than would be compatible with the 2°C limit.
National greenhouse gas emissions in 2021 (left) and between 2000 and 2021 (right) for selected countries. The upper panels show total emissions, while the lower panels show per capita emissions. Figure 2.1 of the 2023 UNEP Emissions Gap Report.
Although China emits more greenhouse gases than any other country currently, it has caused less warming than United States (and slightly more than the European Union) so far. This highlights that high-income countries are primarily responsible for the current warming.
In contrast, the least developed countries, despite representing 14% of the world's population, contribute only 6% of global warming and 3% of current greenhouse gas emissions. According to the report, meeting the objectives of the Paris Agreement requires high-income countries to reduce their emissions and achieve carbon neutrality “faster than the world average”, while providing support to low- and middle-income countries to achieve their climate goals.
There are a limited amount of carbon emissions, the “carbon budget”, to keep heating below 1.5°C.
At the beginning of 2023, there are barely around 250 GtCO2, equivalent to about six years of current emissions, before there is a 50-50 chance of exceeding the 1.5°C threshold. This figure represents a marked decrease since the previous UNEP report, reflecting a recent downward revision in the literature.
Although theoretically, the budget could be expanded using technologies of carbon dioxide removal (EDC), these are still in their infancy and are costly.
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