Glaciers in a third of all World Heritage sites, including Africa’s last remaining glaciers, are “condemned to disappear by 2050”. (AFP)
The world is moving perilously close to the brink of six interconnected risk tipping points that threaten the environment and human security, the United Nations has warned.
These are accelerating extinctions, the depletion of groundwater, space debris, unbearable heat, melting glaciers and an “uninsurable” future, according to the United Nations University.
Human actions are driving this rapid and fundamental change to the planet, according to the university’s new Interconnected Disaster Risks report by the Institute for Environment and Human Security (UNU-EHS). “We are introducing new risks and amplifying existing ones by indiscriminately extracting our water resources, damaging nature and biodiversity, polluting both Earth and space, and destroying our tools and options to deal with disaster risk.”
These systems are “all around us and closely connected to us”, including ecosystems, food systems and water systems. When they deteriorate, it is not a simple and predictable process. “Rather, instability slowly builds until suddenly a tipping point is reached, and the system changes fundamentally or even collapses, with potentially catastrophic impacts.” These, too, can cascade through to other systems and places around the world.
“As we approach these tipping points, we will already begin to experience the impacts,” said Jack O’Connor, lead author and a senior expert at UNU-EHS, in a statement. “Once crossed, it will be difficult to go back. Our report can help us see risks ahead of us, the causes behind them, and the urgent changes required to avoid them.”
Uninsurable future
Since the 1970s, damages from weather-related disasters have increased sevenfold, with last year alone recording $313 billion in global economic losses and severe disasters forecast to double globally by 2040. The report said the number and size of at-risk areas are predicted to expand as climate change shifts the range of hazards such as wildfires and storms into new areas.
“Where extreme weather events increasingly wreak havoc, insurance premiums have climbed as much as 57% since 2015, and some insurance companies in at-risk areas have decided to limit the amount or type of damages they can cover, cancel policies or leave the market altogether.”
It is predicted that more than half a million Australian homes will be uninsurable by 2030, primarily because of increasing flood risk. “The risk tipping point in this context is reached when insurance becomes unavailable or unaffordable, leaving people without an economic safety net when disasters strike.”
Space debris
Space has a garbage problem. When satellites become defunct, they are left in the Earth’s orbit as space debris. Out of 34 260 objects tracked in orbit today, only about 25% are working satellites.
“Additionally, there are likely around 130 million pieces of debris too small to be tracked, measuring between 1mm and 1cm.”
Given that space debris travels at more than 25 000km an hour, even the smallest piece can cause significant damage if it collides with something, creating even more debris.
“The point at which the Earth’s orbit becomes so full of debris that one collision sets off a chain reaction of collisions is identified as another risk tipping point. If that were to happen, the orbit could become unusable, threatening our ability to operate satellites, for example, to monitor the weather and environmental changes and to receive early disaster warnings.”
More than 100 000 new spacecraft could be launched into orbit by 2030, greatly increasing the risk of this tipping point, the report said.
Unbearable heat
Climate change is causing a global rise in temperatures, leading to more frequent and intense heatwaves. This is only expected to become more severe, with extreme heat responsible for an average of 500 000 excess deaths annually in the past 20 years.
Some weather stations worldwide have already recorded temperatures beyond the tipping point for what a human body can survive in. “If this threshold is crossed for more than six hours, even a young and healthy body will suffer extreme consequences.”
The tipping point in this context is a so-called wet-bulb temperature above 35°C, the report said. A wet-bulb temperature is a measurement, which combines temperature and humidity.
High humidity worsens the effects of heat because it hinders the evaporation of sweat, needed to maintain a stable core body temperature and avoid organ failure and brain damage. Wet-bulb temperatures have crossed this critical threshold in at least two weather stations, one in the Persian Gulf and one in the Indus River Basin in Asia.
By 2070, parts of South Asia and the Middle East will regularly surpass this threshold, the report said. By 2100 more than 70% of the global population may be exposed to deadly climate conditions for at least 20 days a year.
Accelerating extinctions
Intense human activities, including land use change, overexploitation, climate change, pollution and introduction of invasive alien species, have created a rate of species extinction at least 10 to 100 times Earth’s natural rate. Ecosystems are built on intricate connections between species. If one species goes extinct, it can have knock-on effects on many others.
“The risk tipping point in this context is when an ecosystem loses key species that are strongly connected, triggering cascading extinctions of dependent species, eventually leading to the collapse of an entire ecosystem.”
Groundwater depletion
Aquifers supply drinking water to more than two billion people, and about 70% of withdrawals are used for agriculture. More than half of the world’s major aquifers are being depleted faster than they can naturally replenish, the report said. “The tipping point in this case is reached when the water table falls below a level that existing wells can access, putting entire food production systems at risk of failure.”
Saudi Arabia was the world’s sixth-largest wheat exporter in the mid-1990s based on large-scale groundwater extraction for irrigation, but wells ran dry and it had to turn to wheat imports. “India and other countries are nearing this risk tipping point, with global impacts expected to ripple through the world’s food systems, economy and environment.”
Melting of mountain glaciers
Because of global warming, the world’s glaciers are now melting twice as fast as they did in the past two decades. From 2000 to 2019, glaciers lost 267 gigatons of ice a year, roughly equivalent to the mass of 46 500 Great Pyramids of Giza.
Glaciers store large amounts of freshwater, and meltwater from glaciers and snow supplies water for drinking, irrigation, hydropower and ecosystems to entire regions.
“The risk tipping point in this context is ‘peak water’ — when a glacier produces the maximum volume of water run-off due to melting. After this point, freshwater availability will steadily decline.”
Peak water has been reached or is expected to occur within the next 10 years for many small glaciers in Central Europe, Western Canada and South America. In the Andes, where peak water has already passed for many glaciers, people “grapple with unreliable water sources for drinking and irrigation”.
More than 90 000 of the glaciers of the Himalayas, Karakoram and Hindu Kush mountains are at risk of reaching the tipping point, threatening the nearly 870 million people who rely on them.
String in a safety net
“If we look at the world as a whole, there are many more systems at risk that require our attention,” the authors said. “Each system acts as a string in a safety net, keeping us from harm and supporting our societies. As the next system tips, another string is cut, increasing the overall pressure on the remaining systems to hold us up.”
Avoiding or adapting to risk tipping points “requires us to fundamentally change how we perceive and value the world around us in a way that gives us the responsibility to care for it”, the authors said.
“We must design our systems to work in a way that recognises how much we need the world and all its systems working together for our survival; otherwise we will find ourselves in a future where risks continue to multiply.”