A day earlier, the European Union-funded Copernicus Climate Change Service said that so far 2023 was 1.43°C warmer than the pre-industrial average, and was “virtually certain” to be the hottest year ever recorded.

The people who lived in these high temperatures would not need the numeric confirmation, though.

Climate Central found that one in four people (1.9 billion) experienced at least a five-day heatwave that was strongly influenced by carbon pollution. These heatwaves had a climate shift index (CSI) of 2 or higher, indicating that human-caused climate change made those temperatures at least two times more likely.

The CSI system quantifies the local influence of climate change on daily temperatures across the globe and estimates how much human-induced climate change shifted the odds of daily temperatures that people experience locally.

These 'highlights' from the report found place in news outlets. But what the headlines glossed over, as they constantly do, was the disparity in impact on the lowest emitters, who unsurprisingly, are also the developing or least developed nations.

Disparate Impact

“This analysis underscores the pattern that climate impacts fall hardest on the countries that have contributed least to the problem,” the "Hottest 12-month stretch in recorded history” report said.

A review of the Climate Central data showed that 79 countries recorded an annual mean CSI of 1.5 and above. Of these, 17 countries were in Asia and 37 in Africa.

In Europe, historically among the highest emitters, none of the countries studied for the analysis recorded that high a CSI.

The continent was responsible for 5,290 million tonnes of CO2 emissions in 2020 (according to data used by Climate Central). In contrast, the African nations studied for the analysis emitted 1,445 million tonnes of CO2.

The worst impact was apparent in Jamaica (Caribbean), where the average CSI over the last 12 months was 4.5 out of a maximum of 5: The highest in the 175 countries studied for the analysis.

This means that on an average day, the average Jamaican experienced temperatures made more than four times more likely by human-caused climate change.

Two other countries — Guatemala (4.4) in Central America and Rwanda (4.1) in eastern Africa — recorded 12-month average CSI values above 4.

The findings are somewhat similar to what Climate Central said in an attribution analysis of temperatures in 180 countries in September, which found that the countries with the lowest historical emissions experienced three to four times more June-August days with CSI level 3 or higher than G20 countries (the world’s largest economies).

The India Story

In India, Climate Central analysed 70 cities across 32 states.

The country recorded an average CSI of 1 but the score increased to 1.6 between May and October this year. In the same period, states like Kerala (3.6), Goa (3.4), Andaman and Nicobar (3.3), Puducherry (3.2), Mizoram (3.0), Karnataka (3.0), Meghalaya (2.9), Manipur (2.8) and Tripura (2.8) recorded high CSIs.

Twelve Indian cities — Bengaluru, Visakhapatnam, Thane, Guwahati, Thiruvananthapuram, Aizawl, Imphal, Shillong, Port Blair, Panaji, Dispur, Kavaratti — experienced over 100 days with a CSI of 5. In 21 cities, including Mumbai and Bengaluru, the people experienced more than 100 days at a CSI of 3 or more.

The large area of many of the G20 countries tends to mask the climate signal when looking at country-wide averages as is the case for India, the analysis said.

The Economic Divide

The latest update, just days ahead of COP28, said that small island developing states of 65 million people (responsible for 152 million tonnes of emissions in 2020) had unusually high average CSI values (2.7) as did the least developed countries (2). In contrast, G20 countries (responsible for 28,477 million tonnes of emissions) had an average CSI of 0.8.

The 10 countries with the highest historical emissions had an average CSI of 0.7, while the 10 lowest emitters had an average CSI of 2.7.

On the economic front, the median per capita GDP of nations with CSI 1.5 and above was $5,153. The corresponding figure for nations with CSI under 1.5 was almost four times: $19,263.

The figures should serve as a reminder for the global community set to meet in Dubai for COP28 to push for stronger commitments on not only emissions reductions but also funds for mitigation and adaptation if the poorer nations are to survive.

Because if the United Nations is to be believed, the situation is set to get worse.

The world is currently on track to produce 110% more fossil fuels by 2030 than would be consistent with limiting warming to 1.5°C, and 69% more than consistent with 2°C, the UN Environment Programme’s Production Gap Report said on November 8.

Catching up with the developed world

While climate impacts are stronger in the developing world, impacts among the richest countries are accelerating, the analysis said.

“Least developed countries and small island nations had higher exposure to climate-driven heat, but climate change touched every country, and intense heat waves occurred in the US, Europe, India, and China," the organisation said in a statement.

This was especially noticeable during the last six months when heatwaves not only hit both hemispheres but also crippled the US and parts of Europe.

While the CSI averaged across the US population was relatively low, several US states had high average CSI values. In the second half of the year, six states — Hawaii (2.8), Louisiana (1.9), Texas (1.9), Florida (1.8), New Mexico (1.8), and Arizona (1.3) — had average CSI values that exceeded 1.

And things will only get harder, for everyone, as the impacts of El Nino manifest next year.

“El Nino impacts on global temperature typically play out in the year after its development, in this case in 2024. But as a result of record-high land and sea-surface temperatures since June, the year 2023 is now on track to be the warmest year on record. Next year may be even warmer. This is clearly and unequivocally due to the contribution of the increasing concentrations of heat-trapping greenhouse gases from human activities,” said WMO Secretary-General Petteri Taalas.

The only thing that remains to be done is to cut emissions.

“We know what we need to do to stop burning fossil fuels. We have the technologies. We have the know-how... But at the moment, we don't do it,” Friederike Otto, a climate scientist and the lead of the World Weather Attribution international panel, said.