In some upbeat news ahead of the COP28 summit in Abu Dhabi, United Arab Emirates, Norwegian analysts Rystad Energy released their Global Energy Scenarios report for 2023, which suggests that through the use of a range of decarbonisation technologies, the world is set to limit global average surface temperature rises to between 1.6 and 1.9^oC. In addition, “new technologies for methane emission reduction are coming, representing an upside of up to 0.2 degree of avoided global warming. Thus, the 1.5-degree target is within reach.”

The report builds its argument on the prediction that primary energy demand will peak at around 630 EJ per annum by around the middle of this decade, as electrification, renewable energies and heat pumps deliver high primary energy efficiencies. As the report states, “of the 500 EJ of primary energy from fossil fuels today, only 250 EJ is used by the end user, while about 440 EJ would be made available if the 500 EJ of primary energy came from solar, wind or hydro.”

Another pillar in the argument is that renewables will be deployed increasingly quickly, and there is reason to believe this. For solar photovoltaics, installations “need to grow from 250 GW new installations in 2023 to 1,300 GW per year in the mid-2030s. This sounds aggressive, however 1,200 GW of named manufacturing capacity is already under construction.” In fact, “the sector is already 29% ahead of the tall order set under the 1.5 degrees Celsius scenario.”

A range of technologies are to be necessary, with the potential for avoided global warming as follows:

• Solar PV: 0.25^oC
• Batteries: 0.12^oC
• Electric vehicles: 0.12^oC
• Chemical absorption carbon capture and storage: 0.12^oC
• Wind power: 0.08^oC
• Hydrogen: 0.08^oC
• Geothermal/heat pumps: 0.08^oC
• Biofuels, high temperature heat storage, circular economy measures, agricultural process changes: 0.15^oC (together)

The analysts see “no major showstoppers like material shortages, but policy support initiatives such as carbon pricing and subsidies are essential to reach the lower end of the [temperature] range”. Shifting from energy molecules to electrons will also reduce materials transportation needs. A peak in global greenhouse gas emissions is expected in mid-2026, while low-carbon investments are expected to surpass those into oil and gas by 2025.

For hydrogen, announced projects do not currently cover the expected need by 2030, meaning that the rate at which projects are announced will need to increase in the coming years. For carbon capture, utilisation and storage, the hugely accelerated deployment/inception rates of recent years have put the technology on a path to meet a 1.6^oC by 2030 (at 600 million tonnes of capture capacity), though project delays or cancellations would put that at threat. Therefore, “solving permitting bottlenecks and financing will be crucial to make sure that these projects are able to deliver as planned.” By 2050, to meet a 1.5^oC target, 8.4 Gt of capture capacity would be required, and to meet a 2.0^oC target, 4.1 Gt of capacity.

Another analysis released recently by the London-based Energy Transitions Commission think tank has also been worth paying attention to. In an opinion piece in the Financial Times, the chair of the commission, Adair Turner, wrote that to meet 2100 global average surface temperature increases of 1.5-1.7^oC above pre-industrial levels, large falls in the use of fossil fuels are needed, combined with the deployment of carbon capture and storage. While the range of applications in which CCS will be needed is narrowing (as, for instance, green hydrogen production and use becomes more viable), it will still play an important role in decarbonisation. It’s estimate is similar to, but lower than Rystad Energy – that around 4 Gt of capture will be required by 2050, with both organisations seeing some role for direct air capture. Mr Turner wrote that both  “we must speed up the deployment of carbon capture and removal technologies” and that, as it would be imprudent to assume that CCS will expand extremely rapidly (more than assumed in their own report), high levels of fossil fuel use will not be possible. Therefore, he concludes that the “world does not need exploration for new oil and gasfields. Indeed, the vast majority of already proven fossil-fuel reserves must be left in the ground.”

The temperature estimates from Rystad Energy are in something of a contrast to projections by the United Nations Environment Programme in its Emissions Gap Report 2023. It states that if “current policies are continued, global warming is estimated to be limited to 3°C. Delivering on all unconditional and conditional pledges by 2030 lowers this estimate to 2.5°C, with the additional fulfilment of all net-zero pledges bringing it to 2°C.” The report found that global greenhouse gas emissions rose by 1.2% from 2021 to 2022, to 57.4 Gt CO₂e, a new record high. Fluorinated gases increased particularly quickly, at 5.5%, while methane emissions rose 1.8%, and nitrous oxide 0.9%. As has long been the case, the least developed countries contribute much less to warming per head of population than developed countries, though individual country performance varies widely. Many industrialised countries’ current policies are not on course to deliver their pledged non-conditional GHG emissions targets, even though most developed countries are on track to reduce their emissions significantly relative to 2015. The report states that the “failure to stringently reduce emissions in high-income countries and to prevent further emissions growth in low- and middle-income countries implies that all countries must urgently accelerate economy-wide, low-carbon transformations to achieve the long-term temperature goal of the Paris Agreement”. For another comparison, the Climate Action Tracker website, as of November 2023, has 2100 temperature estimate ranges of 2.2 to 3.4^oC based on current policies, 1.9 to 2.9^oC based on 2030 targets, 1.6 to 2.5^oC based on binding long-term targets, and 1.5 to 2.3^oC based on the implementation of all announced targets.

Some of these estimates are quite close to each other, while others vary considerably, especially when keeping in mind reports such as the IPCC’s Global Warming of 1.5 ºC report from a few years ago, which emphasised how different the climate change impacts are of just half a degree Celcius of warming. The differences in the estimates stem from different ways of viewing the future – one (Rystad and, to a lesser extent, the Energy Transitions Commission) being from the viewpoint of the deployment of technology, and the other (UNEP, and also Climate Action Tracker) being from the viewpoint of the deployment of policies and goals. Technology deployment of course relies partly on policy settings, but one must hope that the technologists’ predictions will prove to be the more accurate. In their favour, they seem to consider the rate of change of decarbonisation technologies.