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Global warming on course for 2.9C, UN report warns

Action continues to fall far short of pledges, even as temperature and greenhouse gas records are repeatedly broken
<p>Wildfire burning atop a mountain in the northern suburbs of Athens, Greece, in July 2022 (Image: Alamy)</p>

Wildfire burning atop a mountain in the northern suburbs of Athens, Greece, in July 2022 (Image: Alamy)

Countries must make far greater efforts to implement their climate strategies this decade to stand a chance of keeping global temperature rise within 1.5 degrees Celsius of the pre-industrial average.

Continued delays will only increase the world’s reliance on uncertain carbon dioxide removal technologies (CDR), according to the UN Environment Programme (UNEP).

In its latest annual assessment of progress on global climate action, the Emissions Gap Report 2023, UNEP looks at progress since the Paris Agreement. When it was adopted in 2015, greenhouse gas emissions were projected to rise 16% by 2030. Today, that increase is projected to be 3%.

But from now, emissions must fall 28% by 2030 to keep temperature rise to 2C, or by 42% to stay within 1.5C, and countries are failing to match this need with action, UNEP found.

Current climate policies will result in a rise of 3C this century. The increase will be limited to 2.9C if countries fully implement their national climate plans (known as Nationally Determined Contributions, or NDCs).

This could be kept to 2.5C if plans by developing countries, which are currently conditional on obtaining financial support, are carried out – since that would result in a 9% fall in emissions.  

In UNEP’s most optimistic scenario, where all conditional NDCs and net zero pledges are met, limiting temperature rise to 2C could be achieved, UNEP says. This scenario is considered to give at best a 14% chance of limiting warming to 1.5C.

Currently, 97 countries have pledged to meet net zero emissions by a target date, up from 88 last year. Pledges cover 81% of the world’s greenhouse gases. However, the authors of the UNEP Emissions Gap Report do not consider these pledges to be credible, pointing out that none of the G20 countries are reducing emissions at a pace consistent with their net-zero targets.

National net zero plans have several flaws, according to Anne Olhoff, chief scientific editor of the report. Many are not legally binding, or lack clear implementation plans, while mid-term targets between now and the dates when governments claim to be aiming for net zero are missing, she says.

Emissions are still going up in countries that have put forward zero emission pledges
Anne Olhoff, chief scientific editor of the UNEP Emissions Gap Report 2023

“But most importantly, emissions are still going up in countries that have put forward zero emission pledges. There are many ways to net zero, but at some point you need to peak and reduce. And the longer you wait until you peak, the more difficult it’s likely to be to actually get to net zero,” she says.

Under the Paris Agreement, ambition in the NDCs is designed to be ramped up over time. At COP28, which begins in Dubai at the end of November, countries will debate how to build new ambition under the first Global Stocktake. This will inform the next round of NDCs to be submitted in 2025, which will have targets for 2035.

Countries should focus on implementing existing policies this decade, rather than pledging higher targets for 2030, says Olhoff.

“Whether or not the ambition of the 2030 targets is raised or not is less important than achieving those targets. If countries find that they can also strengthen ambition for 2030, that’s an added benefit,” she says.

The more action taken this decade, the more ambitious countries can be in their new targets for 2035, and the easier it will be to achieve those targets, she points out.

The UNEP Emissions Gap Report states that high-income and high-emitting countries within the G20 should take the most ambitious and rapid action, and provide financial and technical support to developing nations.

However, it adds that low- and middle-income countries already account for more than two-thirds of global greenhouse gas emissions. Development needs in these countries should be met with economic growth that produces low emissions, such as by reducing energy demand and prioritising clean energy, it says.

“This [low- and middle-income countries] is an extremely large and diverse group of countries, and the opportunities for low-emissions growth depend a lot on national circumstances,” Ohloff says. Proposed reforms to international finance through multilateral development banks should improve access to finance and the ability of developing countries to attract investment, given that borrowing often costs substantially more than in developed countries, she says, adding that those that suffer from corruption need to “get their own house in order” and improve governance.

The role of carbon removal

The Emissions Gap Report points out that the world will also need to use carbon dioxide removal (CDR) to keep warming under control. The report authors say that CDR can already contribute to lowering net emissions today, and in the medium term can contribute to tackling residual emissions from so-called ‘hard-to-abate’ sectors such as aviation and heavy industry.

In the longer term, CDR could potentially be deployed at a large enough scale to bring about a decline in the global mean temperature, the authors say. They stress that its use should be in addition to rapid decarbonisation of industry, transport, heat and power systems.

CDR refers to the direct removal of carbon from the atmosphere and its durable storage in geological, terrestrial or ocean reservoirs, or in products. It is different to carbon capture and storage (CSS), which captures carbon from emissions at their sources, such as a power station, and transfers it into permanent storage. While some CCS methods share features with CDR, they can never result in carbon removal from the atmosphere.

aerial view of power station
The Drax power station in northern England burns wood to generate electricity, and plans to start capturing carbon dioxide before it goes up the stack, liquefying it to reduce its volume and then burying it out of harm’s way (Image: Alamy)

Some CDR is already being deployed, mainly through reforestation, afforestation and forest management. However, this is currently very small in scale, with removals estimated at 2 gigatonnes of carbon dioxide equivalent (GtCO2e) annually. Research and development into more novel technologies is increasing, with methods including sequestering carbon in soil; enhanced weathering, which speeds up the natural weathering of rocks to store CO2; and direct air capture and storage (DACC), where CO2 is extracted from the atmosphere.

There are multiple risks associated with scaling up CDR. These include competition with land for food, and protection of tenure and rights. In addition, the technical, economic and political requirements for large-scale deployment may not materialise in time, UNEP says. Some methods are very expensive, particularly DACC, which UNEP estimates to cost USD 800 per tonne of CO2 removed.

Governments have tended not to specify the extent to which they plan to use CDR to achieve their emission-reduction targets, nor the residual emissions they plan to allow annually when achieving net-zero CO2 and greenhouse gas emission targets, UNEP found. Estimates of the implied levels of land-based removals in long-term strategies and net-zero pledges are 2.1-2.9 GtCO2 of removals per year by 2050, though this is based on an incomplete sample of 53 countries, the report notes.

Politicians must coordinate the development of CDR, the report states. Oliver Geden, lead author of the chapter on CDR, explains that governments need to clarify its role in national and global climate policy, and develop standards for measuring, reporting and verification (MRV) that can eventually be included in national greenhouse gas inventories under the UN climate change process.

“At COP28, the [Global Stocktake] decision could clarify the role of CDR in global climate policy and demand the inclusion of CDR as a separate item in NDCs for 2035, which are due by 2025,” he says.