28th August, 2024 in Natural World

Wildfires humanity has to face

By Ian Hembrow

Ian Hembrow, author of Celsius: A Life And Death By Degrees, reveals the bigger story behind the world’s increasingly frequent and ferocious summer wildfires.

As I watched the television news, an announcement scrolled across the screen: ‘Authorities in Greece say wildfires are under control’. Good news I thought, having followed coverage of the fatal inferno that had consumed 40 square miles of land close to Athens, the historic town of Marathon and packed tourist centres nearby over the preceding few days. The bad news though is that, globally, wildfires are anything but under control. They are just one symptom of a climate system undergoing rapid – largely human-induced – change, which will profoundly affect all of our lives, and those of future generations. So what’s going on?

Fire is a season

In parts of Canada, the United States, Brazil, Russia, Australia, Indonesia, northern and southern Europe, fire is now a season: a predictable and steadily lengthening annual period in which vast wildfires are no longer just a likely risk but a deadly certainty. And the average temperature records we see being broken every year and every month drive the scale and incidence of wildfires still faster and further. This new reality is not something we can avoid or run from – it has to be faced.

The relationship between climate change and wildfires operates as a closed feedback loop. The hotter the planet becomes, the more moisture evaporates from the land, making forests drier and more susceptible to fire. When they burn, huge quantities of particles and pollutants are ejected into the atmosphere to contribute to the greenhouse effect.

Particles blown to the polar regions also settle on snow and ice, darkening the surface and so reducing its ability to reflect heat. This in turn causes ice sheets to melt faster, altering ocean salinity and currents, which lead to even warmer temperatures. The ice caps’ retreat then exposes more permafrost, releasing greater emissions of methane, more global warming and more fires. And so on.

It’s thought that a faulty power cable started the fire in Greece. While it was lightning that sparked the 100-feet-high flames that destroyed almost half of the mountain town of Jasper in Alberta, Canada, a few weeks before. Other fires – like one that raged across the island of Tenerife between August and November 2023 – are started on purpose. It’s estimated that around 60 per cent of all wildfires are the result of deliberate or reckless human action. And the conditions created by industrialisation and burning fossil fuels are of course 100 per cent down to us.

A human problem

Some kinds of forests and grasslands have evolved to burn. It’s an essential part of how trees, plants, soil, fungi and microbial life regenerates that from time-to-time woodlands spontaneously ignite. This is most often due to lightning strikes as in Jasper, or through resin reacting to exceptionally hot weather. But by steadily encroaching into forests and turning them into resources to be exploited and managed, humans have upset these cycles. Habitats that might previously have burned every 300 years are now igniting every 30 years, giving natural resources and defences no time to recover in between.

Small fires, the sort that keep natural revival ticking over, have become much less frequent; easily prevented by modern stewardship or controlled by quick-response firefighting. But as average temperatures and extreme weather events increase, the risk of unstoppable super-fires becomes greater. Across the world, annual wildfire seasons are already forty to eighty days longer than they were in 1990. So although there are now fewer fires per year in total than ever before in recorded history, the areas of land they affect and the loss and destruction they cause have gone off the scale.

During the ‘Black Summer’ of 2020 when the size and impact of forest fires really began to gain worldwide attention, the 45 million acres destroyed in Australia alone was equivalent to a country the size of Uruguay, Cambodia or Syria. It’s estimated that almost three billion animals were killed or displaced in the 2020 Australian fires: mammals, reptiles, birds, amphibians, invertebrates and insects.

Wildfires can be mitigated – for example, by clearing accumulated ground-level biomass that provides the tinder for them to start and spread. They can also be fought – by ingenious water-bombing aircraft or by using artificial intelligence to predict exactly where fires will happen next. But by focusing on these more immediate measures, we inadvertently predispose forests to burn under the very worst conditions. This paradox means that the more we try to prevent and suppress fires in the near term, the worse they become when they return. And many of these initiatives undermine the biodiversity and ecological value of the world’s great forests.

Heat domes are here

When an enormous tract of woodland burns, it releases millions of tonnes of carbon and gases into the atmosphere. In recent years, this has contributed to more frequent ‘heat domes’ settling over continental regions, where a static high pressure weather system traps hot air beneath it like the lid on a pressure cooker, causing temperatures to soar past 50 degrees Celsius. When a heat dome forms, any humans beneath it are in trouble, because the ‘wet bulb’ temperature can rise beyond the point at which even the healthiest people can survive.

Our species stays cool by sweating. In hot weather, the salty droplets that emerge from our pores evaporate to cool the skin and bring down the body’s temperature. But this can only happen if the air is dry enough to take up more moisture. Once relative humidity reaches 95 per cent or above, sweat simply collects on the skin, making us feel even hotter and stickier. And when these levels of humidity combine with extreme warmth, people can quickly overheat and die from heatstroke – as recently happened in northern India.

Climate forecasters previously thought that this fatal combination might begin to occur by the middle of the twenty-first century. But it has arrived and taken hold much sooner than expected. Inside a sweltering heat dome, air conditioning is one of the few short-term options for survival. Refuge from unbearable heat and humidity, even temporarily, allows the body to recover and rebalance. But millions of air conditioning units consuming energy and pumping out hot air just make the underlying problem worse, driving the feedback loop of emissions, warming and climate distortion ever faster and deeper.

Because of the region’s size and relatively sparse population, the 2021 North American heat dome killed only a few hundred people. But even those in perfect health who stayed in the shade, with an endless supply of water and wearing clothes that made it easy to sweat succumbed. Localised peaks of heat and humidity simply made it thermodynamically impossible to prevent overheating and death. In more populous countries like India or China, this phenomenon has the potential to kill tens of millions in days or weeks; a mass human extermination like none ever seen before. And on our current trajectory it’s a matter of when, not if, this happens.

Living with wildfires

Forest fires are natural, essential and often uncontrollable. So if we are to live with them it’s our own habits and choices that need to change. If we know that parts of the world are virtually guaranteed to burn, then it makes little sense to locate settlements and industries there. Instead we need to let natural forces reassert their control in these regions and find ourselves other places and models to live and work.

The nature and scale of the change needed to achieve this take the challenge far beyond the individual. It demands new paradigms of human communication and cooperation, innovative technologies and concerted global action that can be sustained over centuries or millennia. We know for certain that we face a hot, fiery future, so societies will have to learn and act quickly to protect our fragile home.

Following the fires near Athens, Greek Prime Minister Kyriakos Mitsotakis visited a military airbase to thank the crew of firefighting aircraft for their efforts and bravery. At the same time he bore an apology – that it would be another three years before seven new water-carrying planes purchased from Canada are due to arrive.

Time, it seems, is not on our side.