The governments of highly emitting countries have a critical opportunity to accelerate emissions reductions through ambitious revisions of NDCs at COP26, significantly enhancing policy delivery mechanisms, and incentivizing rapid large-scale investment in low-carbon technologies.
Unless NDCs are dramatically increased, and policy and delivery mechanisms commensurately revised, many of the climate change impacts described in this paper are likely to be locked in by 2040, and become so severe they go beyond the limits of what nations can adapt to. If emissions follow the trajectory set by current NDCs, there is a less than 5 per cent chance of keeping temperatures well below 2°C above pre-industrial levels, and less than 1 per cent chance of reaching the 1.5°C Paris Agreement target. There is currently a focus on net zero pledges, and an implicit assumption that these targets will avert climate change. However, net zero pledges lack policy detail and delivery mechanisms, and the gap between targets and the global carbon budget is widening every year.
If emissions do not come down drastically before 2030, then by 2040 some 3.9 billion people are likely to experience major heatwaves, 12 times more than the historic average. Temperature increases are already resulting in the equivalent of over half of COVID-19-induced lost working hours. By the 2030s, 400 million people globally each year are likely to be exposed to temperatures exceeding the workability threshold, and the number of people exposed to heat stress exceeding the survivability threshold is likely to surpass 10 million each year.
To meet global demand, agriculture will need to produce almost 50 per cent more food by 2050. However, yields could decline by 30 per cent in the absence of dramatic emissions reductions. The probability of a synchronous, greater than 10 per cent crop failure across the top four maize producing countries, which together account for 87 per cent of exports, during the decade of the 2040s is just less than 50 per cent.
Cascading climate impacts will likely cause higher mortality rates, drive political instability and greater national insecurity, and fuel regional and international conflict. During an expert elicitation exercise, the cascading risks that experts had greatest concern over were the interconnections between shifting weather patterns, resulting in changes to ecosystems, and the rise of pests and diseases, which combined with heatwaves and drought will likely drive unprecedented crop failure, food insecurity and migration. Subsequently, these impacts will likely result in increased infectious diseases, and a negative feedback loop compounding each of these impacts.
The governments of highly emitting countries have a critical opportunity to accelerate emissions reductions through ambitious revisions of NDCs at COP26, significantly enhancing policy delivery mechanisms, and incentivizing rapid large-scale investment in low-carbon technologies. This will lead to cleaner and cheaper energy, and avert the worst climate impacts.