Climate Connections - Extreme Weather & Heatwaves
In this mini-series, we investigate some of the impacts of climate change that are having a worldwide impact, and which may therefore have the potential to generate a worldwide response.
It is very clear that the world consensus on the need to take concerted action on climate change is frayed, with some countries wandering off to pursue their own policies, or having no policies at all beyond pretending that none of this is happening.
We want to remind readers that climate change is not a series of isolated events that can make us pause for a moment, and then move on. Rather it is a worldwide and connected phenomenon, we are all unwitting participants, and we might as well all start asking how we can contribute to solutions.
In this first article we consider Heatwaves and related extreme weather. In future articles we will look at Glaciers and Ocean warming.
Overview
In their annual summary published in late 2024, ‘When Risks Become Reality: Extreme Weather in 2024’, World Weather Attribution, Climate Central and Red Cros Red Crescent Climate Centre sum up the impacts of extreme weather in 2024.
Four billion people, 49% of the world’s population, experienced 30 extra days of extreme heat (hotter than 90% of the average for their area for 1991-2020), and this was made two times more likely by human-induced climate change.
The study notes drastic effects of droughts and wildfires in the Amazon and Pantanal in 2024. The same impacts were also noted by the EU weather satellite Copernicus Atmosphere Monitoring System.
In March 2025, World Weather Attribution recorded record temperatures for Central Asia, with 30.8°C in Jalalabad, Kyrgizstan, and 29.1°C in Fergana, Uzbekistan. The same figures were picked up in reporting from Poland.
In late May 2025, World Weather Attribution, and others, noted record-breaking heatwaves in Iceland and Greenland. On 15 May 2025, the temperature at Egilsstaõr Airport, in Iceland, was 26.6°C. Across Iceland, average temperatures were 13°C hotter than for the same month over the period 1991-2020. Greenland’s ice sheet was reported to be melting at 17 times the normal rate, made 3°C hotter by climate change, as reported in the Hindustan Times. The same paper reported a separate study predicting a doubling of heatwave days and extreme rainfall expected for most major Indian cities by 2030, with major impacts on Gujurat, Rajasthan, Tamil Nadhu, Odish, Uttarakhan, Himachal Pradesh, Maharashtra and Uttar Pradesh.
Attributing Extreme Weather to Climate Change
With the Paris agreement, nations agreed to make their best efforts to keep global average temperatures from rising 1.5°C above pre-industrial averages. We are 1.28°C warmer today than pre-industrial times. Compared to the spike in temperatures seen during a heat wave this does not seem like much, so how do we know extreme weather is due to climate change?
Firstly, the science tells us that the global warming that has already happened has had a big impact on local temperatures and the balance of weather systems across the world. The IPCC says:
Human-induced greenhouse gas forcing is the main driver of the observed changes in hot and cold extremes on the global scale (virtually certain)
Human influence, in particular greenhouse gas emissions, is likely the main driver of the observed global-scale intensification of heavy precipitation over land regions
More regions are affected by increases in agricultural and ecological droughts with increasing global warming (high confidence)
As temperatures further increase, these effects will get stronger and stronger.
Attribution science
A growing field of climate science takes climate models, and predicts the likleyhood a certain event would happen with and without man-made global warming. It is a relatively new field of research, and has so-far looked at specific events, such as hurricanes, heatwaves and wildfires, and attempted to quantify how much climate change increased the severity and likelyhood of the event.
Being able to quantify the % likelyhood of events being influenced by climate change is already playing a crucial role in lawsuits over damages from extreme weather events.
You can read more about how these studies are conducted here.
Pakistan, June 2025
So far we have given the context of world wide climate change and extreme weather events, but its local affect can be seen with what is happening this month in Pakistan.
The extreme, scorching temperatures are back, with direct health effects, especially upon the elderly, children and those working out of doors, like labourers and rickshaw drivers, and those in homes without air conditioning.
In June 2025, it was reported that almost all cities in the Punjab were over 45°C, with Bhakkar and Jacobabad in Sindh both recording 49°C, Karachi – 40°C with 70% humidity, Mohenjo-Daro – 48°C, Peshawar, Khyber Paktunkhwa – 45-46°C, Lahore 46.2°C
The National Disaster Management Authority issued a heatwave alert for the whole country, which looked like this:
Wet Bulb Temperature
When heat and humidity are combined, heatwaves are even more deadly. It was thought that the human body could not regulate its temperature if the so-called wet-bulb temperature was 35°C, but a recent study found that “critical wet-bulb temperatures ranged from 25°C to 28°C in hot-dry environments and from 30°C to 31°C in warm-humid environments.”
If you want to read about what could happen during a hot & humid heatwave, we recommend reading the first chapter of Kim Stanley-Robinson’s Ministry of the Future, which depicts a harrowing fictionalised heatwave in India.
The heatwave accentuates the issue of fair distribution of water resources even within Pakistan, let alone with its regional neighbours, with arguments about the fairness and impact of new canals in the Punjab and their impact on downstream areas of Sindh.
We do not profess in this article to have all the answers. World Weather Attribution state that their 2024 report showed the need for -
Faster shift from fossil fuels
Improvements in early warning
Real-time reporting of heat death
Finance for developing countries
All of these can be important, along with simple measures to mitigate heat stress.
ICIMOD is investigating improved systems of Community Based Flood Early Warning Systems.
Understanding of programmes such as tree planting in cities is advancing, with one University of Cambridge study underlining the need to plant the right kind of trees for the right climate.
Other studies including one by the University of Oxford underline the potential for reflective roof surfaces to reduce overheating and save lives during heatwaves.
A good list of actions communities can take efore heatwaves has been complied by FirstStreet