An old song earworms its way through my mind, the lyrics ‘it’s getting hot, hot, hot’ tripping over a punchy soca rhythm. I can’t place it but recognise it as an intermittent visitor for some months. It’s as though the zeitgeist is bubbling up into my consciousness, fuelled by an unending wave of newspaper headlines warning of heat all over the world that is unmatched – and yet soon to be surpassed.
Each of the last four decades has been in turn warmer than the one before since 1850. We are now at roughly 1.1 or 1.2 degrees C above pre-industrial levels. And the rate of temperature increase is rising – it is getting hotter faster. Weather records show that since 1970, global surface temperature has climbed faster than in any other 50-year period over at least the last 2,000 years.
Heat is both a driver of climate change and an impact.
The fundamental issue is the increasing energy or heat imbalance in the planetary system. Because we are putting more greenhouse gases like carbon dioxide into the atmosphere, primarily through burning fossil fuels to drive our economies and power transport, more heat is trapped in the atmosphere.
This heating drives a myriad of changes: shifting wind patterns, changes in moisture gradients, disturbances to ocean currents. Heating of the climate system has also caused global mean sea level to rise as ice on land melts and the warmer oceans expand.
So the shifts in the climate system are more complex than ‘it’s getting hotter’ – we also have more variable and thus harder to predict weather, extra droughts, heavier and/or more erratic rainfall, and more powerful cyclones. Weather systems like cut-off lows are now more prone to stalling and dumping a month’s rain in one day. And a whole host of other outcomes.
Sometimes different effects occur in quick succession in the same area – the southern province of Sindh in Pakistan was assailed by widespread flooding in June 2022 one month after a farmers’ group called for it to be declared drought-stricken as it was experiencing 70% water scarcity.
Secondly, heat is also a direct impact – which in turn drives further change, but more about that later. Humans, plants and animals are affected by hotter average temperatures as well as more and longer heatwaves.
Human – and other animal – bodies struggle to regulate temperature when it is extremely hot, leading to heat cramps, heat exhaustion, heatstroke, and worse. People can become unwell and die rapidly in heatwaves, especially those who are frail or have chronic conditions like diabetes or cardiovascular disease.
As well as harming human health, increased heat stress affects productivity and GDP; biodiversity and ecosystems, by reducing the viable range of species and varieties; and the yields from crops and livestock.
It seems intuitive and is also scientifically demonstrated that increasing heat is linked to more frequent severe droughts, through a combination of sustained heatwaves, higher rates of evapotranspiration and higher rainfall variability.
The drought-heatwave double punch has been trending big this year. Europe suffered its worst drought in 500 years, in one of the hottest summers ever recorded. Heatwaves are now so severe that Spain has started giving them names, the way hurricanes are named.
And what were the consequences of this heat? Over 24,000 heat-related fatalities – yes, in Europe, and the worst fire season ever recorded. The heat plus exceptionally low rainfall led to parched soils in France, Germany and other countries in Western and Central Europe. Climate change made the European drought twenty times more likely.
As Europe sweltered, parts of China and North America suffered intense heatwaves. The recent widespread heat in the Arctic and across Africa has been ‘unprecedented’ – an overused word in these times.
And now a terrible drought in Somalia – five rainy seasons in a row, and counting, have failed – is rapidly becoming a famine. It is hard to fathom, but in the 2011 famine in Somalia, 260,000 people died, many of them children.
Our hotter atmosphere, land, and oceans have caused – and will continue to drive – widespread and rapid changes in the earth system that affect climate patterns, ecosystems, and human societies and economies. The stable climate that bolstered our development is gone forever.
We are already seeing the marks on agriculture and food systems. Thanks to climate change, Africa’s growth in agricultural productivity is 34% down since 1961 – a decline greater than in any other part of the world. As the planet continues to warm, shorter growing seasons and increased water stress will reduce the crop yields of African farmers across most of the continent.
Back up north, a quarter of the world’s olive oil comes from the 67 million olive trees in the drought-ravaged province of Jaén in Spain. Dry Mediterranean areas have been ideally suited to olive oil production for centuries – but even hardened olive trees need some water. Although farmers can deploy irrigation, it adds to expenses and is pushing some long-time producers out of farming.
The dilemma facing Spain’s olive oil farmers, and similar difficulties experienced by smallholder farmers all over the world, foreshadow the huge potential impacts not only on the viability of farming livelihoods, but also on rural people’s identities and cultures.
I was recently interviewed for the new podcast series ‘Ready or Not, Change is Coming‘ on ‘Heat’ – not my main area of expertise, but anyone working on climate change nowadays has to have more than a passing acquaintance with this new ‘frenemy’. And my takeaway messages were about the insidious nature and the dangers posed by growing heat.
It’s easy to miss this if you are not directly in the firing line. Another warm spell in October on this chilly isle – ooh, how lovely. My spirits lift in the sun and my shoulders release. But while a slightly warmer autumn feels like balm in a temperate area, the unseasonal warmth has an ominous undertone.
There are not many winners from increased heat, even in the short term. In spring we are seeing a de-coupling of the carefully co-evolved relationships between plants and their pollinators, that can be disastrous for agriculture and ecosystems.
Even small rises in average temperature in the world’s very hot places can mean the difference between surviving or not, for many species and people. In India, almost every weather station has shown increasing trends in heatwaves; in the six years prior to 2019, the state of Andhra Pradesh (population just under 50 million) has experienced heat waves almost every year, with longer heat periods in every part of the state.
And there is worse to come – for example, in Sri Lanka the number of days hotter than 35°C could rise from 20 days to more than 100 days by the 2090s under high emissions scenarios (under RCP8.5).
Heat’s effects on health are not restricted to India and Sri Lanka. Communities all over the world already experience significant levels of heat-related ill health, diarrhoeal disease, and malnourishment.
Being physically active and not sufficiently hydrated in recurring heat can lead to chronic kidney disease (CKD). Health problems arising from ongoing heat prevent farmers from productively engaging in livelihood activities, substantially increase family medical expenses, and weaken the rural economy and farmers’ ability to withstand losses from livelihood activities. Women and girls are affected more, as this adds to their already heavy load of unpaid care work. Children can’t concentrate and learn as well in extreme heat.
In northern latitudes, we may think that the thawing of permafrost due to increased heat is favourable because it opens up huge new areas for agriculture, but previously frozen areas face massive costs as roads and structures buckle and crack from subsidence as ice in the land under them melts. The inhabitants of Shishmaref in Alaska have voted to relocate because thawing permafrost is increasing coastal erosion and destabilising their homes and water systems. And we are already seeing the emergence of new – or old but newly released pathogens – from melting of permafrost and from changes in mean temperatures.
What many people don’t understand is that when scientists talk of an increase in 1.5 degrees temperature above pre-industrial times, this is the global average surface temperature, averaged out for land and seas. Many terrestrial areas already have an increased average surface temperature that is already much hotter than the global average. As the IPCC notes, in 2011-2020, increases over land averaged out at 1.59 °C already, while over the ocean, the average surface temperature was 0.88 °C.
So at ‘1.5’, the world’s land areas will be quite a bit hotter than that goal of the Paris Agreement. And already about 30% of the world’s population is exposed to deadly heat stress. This is projected to increase to between 48% to 76% of the people in the world by 2100, depending on future warming levels and location.
Hotter air means wetter air because it can hold more moisture. This not only means more intense rainfall and cyclones, but also increased heat stress risk as the critical temperature threshold drops. To oversimplify the wet-bulb temperature effect, you can’t sweat as much in humid air and so your body’s cooling mechanisms are reduced.
The thresholds beyond which people cannot survive extreme heat and humidity could be reached over the next few decades in the Sahel and the Horn of Africa, as well as south and southwest Asia, according to a new UN / Red Cross report. Agricultural workers, older people, children, and pregnant and breastfeeding women are at higher risk of illness and death. 700% more poor people in urban areas, especially in West Africa and South-East Asia, will live in extreme heat. In Europe, two or three times as many people will be at risk of heat stress if temperatures go up to 3°C global warming compared to 1.5°C above pre-industrial levels.
Like a silent partner, the oceans have absorbed more than 90% of the heat caused by increased greenhouse gases since the industrial revolution. But this backroom action can’t continue forever as the seas get hotter, deeper. Heating of the top 2km of the oceans has accelerated since the 1960s, escalating sea level rise and intensifying heavy rains – for example, worsening the recent floods in eastern Australia – and making cyclones more powerful.
Marine heatwaves are bleaching coral reefs and causing widespread die-offs in marine plants and animals. A recent study has emphasised that even with rapid emissions reductions and net-zero carbon emissions in 2050, the oceans will get hotter and sea levels will continue to rise for several centuries. And as the oceans get hotter, they can absorb less carbon dioxide from the atmosphere. It’s a not-so-merry-go-round.
Enough already with the bad news. What can be done? Rapid, deep, extensive, real emissions cuts – as soon as possible. And serious attention to and investment in widespread adaptation measures, with health, human rights, and ecology at the centre. No more subsidies to dirty industries, no more double counting of adaptation money, no more obfuscation.
I finally conduct a simple search which reveals that the song still coursing through my head is ‘Hot, Hot, Hot’ written and first released in 1982 by Alphonsus Cassell, from Montserrat in the Caribbean.
Cassell, aka Arrow, said that “’Feeling Hot Hot Hot’ makes you forget that there’s a volcano and remember there’s fun to be had.” He also said, when explaining the difference between calypso and soca, that soca was made for dancing and did not “carry any political messages”.
It’s hard to forget our ‘volcano in the room’ as heat blasts through our lives – in the air, in politics, and in blatant aggressions by nationalistic leaders. But there is still life to be lived, fun to be had, and beauty all around us. Let that fuel our hope – which is not the same as optimism, in the words of Vaclav Havel, but rather the conviction that “something makes sense” – in this case, our actions to mitigate climate change – “regardless of how it turns out”.
It’s getting hot, hot, hot. Unlike a soca song, we do need that political message to get through – and to be acted upon with urgency. Time for a cooling draught of political maturity and global compassion at COP-27 in Sharm-el-Sheikh in 10 days’ time.
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