The world is set for a "catastrophic temperature rise" of up to 3.1°C above pre-industrial levels, unless there is a "G20-led massive global mobilisation to cut all greenhouse gas (GHG) emissions", the UN Environment Programme (Unep) said today in its Emissions Gap 2024 report.
It is still "technically possible" for the world to meet the 1.5°C temperature goal set out in the Paris climate agreement, but only with significant effort, the report found. If current commitments for 2030 are met, temperature rise would be limited to 2.6°C-2.8°C above pre-industrial levels. The Paris agreement seeks to limit warming to "well below" 2°C and preferably to 1.5°C.
The 2.6°C scenario is based on the "full implementation" of countries' current national climate plans, known as nationally determined contributions (NDCs). But "continuing with current policies only would lead to 3.1°C of warming", Unep said.
Countries are due to submit updated NDCs, which would cover a timeframe up to 2035, by February next year. And they "must collectively commit to cut 42pc off annual GHG emissions by 2030 and 57pc by 2035… and back this up with rapid action" in the next round, or the 1.5°C goal "will be gone within a few years", Unep said. The emissions cuts needed are relative to 2019 levels, but GHG emissions reached a record high of 57.1bn t/CO2 equivalent (CO2e) in 2023.
To get on track to keep global warming below 2°C, GHG emissions must fall by 28pc by 2030 and 37pc by 2035, both from a 2019 baseline, the report found.
The global average temperature for the 12 months from October 2023 to September stood at around 1.62°C above the pre-industrial average, according to EU earth-monitoring service Copernicus. It is "almost certain that 2024 is going to be the warmest year on record", Copernicus added.
Invest and implement
To ensure that warming is limited to below 2°C by 2030, annual emissions should be 14bn t/CO2e lower than the rate implied by current unconditional NDCs. This refers to elements of the plan that a country pledges to carry out with no external support, whether technical or financial. To hit the target of limiting warming to 1.5°C, annual emissions should be 22bn t/CO2e lower than current unconditional NDCs suggest over the same timeframe.
There is "technical potential" for GHG emissions cuts of up to 31bn t/CO2e and 41bn t/CO2e in 2030 and 2035, respectively, the report found. This would "bridge the gap to 1.5°C in both years", and cost less than $200/t of CO2e, it added.
Increased deployment of solar and wind power could provide 27pc of the total GHG reduction potential in 2030 and 38pc in 2035, Unep said. And "action on forests" — which are key carbon sinks — could deliver around a fifth of the potential in both timeframes, it added. Electrification and efficiency measures in the transport, buildings and industry sectors would also cut GHG emissions.
But a "minimum six-fold increase in mitigation investment" is needed for the world to reach net zero emissions, the report found. The estimated incremental investment is between $900bn and $2.1 trillion annually over 2021-50. This would "bring returns in avoided costs from climate change, air pollution, damage to nature and human health impacts", Unep said.
Members of the G20 group of countries, which are responsible for the majority of global emissions, are off track to meet their current goals and must "take the lead by dramatically increasing action and ambition" in new NDCs, Unep said. G20 members, without the recent addition of the African Union as a permanent member, accounted for 77pc of emissions in 2023.
The outlook has worsened since last year's Emissions Gap report, which flagged a temperature rise of 2.5°C-2.9°C.
