11 looming climate tipping points that imperil our planet
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The world is rapidly approaching the "brink of multiple risk tipping points," the United Nations said in its 2023 Interconnected Disaster Risks report. Risk tipping points, the U.N. said, are "when the systems that we rely on for our lives and societies cannot buffer risks and stop functioning." Throw in accelerating climate change, and "the very practical consequence will be that much more people will live under very precarious conditions — so loss of life, loss of livelihood and loss of opportunities," Zita Sebesvari, one of the lead authors of the report, said to the Los Angeles Times. "It does have cascading impacts."
A new report by the University of Exeter Global Systems Institute specifically pointed to three broad areas where tipping points are concentrated: the cryosphere, the biosphere and the ocean and atmosphere. The world is soon to meet several tipping points but we can still "take decisive actions to avert the worst of these impacts, and perhaps even forge a new path toward a bright, sustainable and equitable future," the U.N. report said.
Cryosphere tipping points
Mountain glaciers melting: As aquifers empty, the world's glaciers are "melting at double the speed they had in the past two decades," the U.N. report said. That increases the amount of freshwater in the short term — sometimes too much, causing flooding — but "many of those glaciers in the Rocky Mountains, the Himalayas and the Andes feed into these rivers and groundwater systems," Caitlyn Eberle, one of the lead authors of the U.N. report, said to Reuters. "So as those glaciers disappear, there is less water available." Many glacier-fed areas are rapidly approaching or have already reached "peak water," the point of maximum meltwater a glacier produces before its freshwater output steadily declines. Meltwater is crucial to sustaining certain regions during dry seasons with low rainfall.
Greenland ice sheet collapsing: The Greenland ice sheet is a staggering 1.71 million square kilometers, only second in size to the Antarctic ice sheet. The sheet is also losing mass as the climate warms and "substantial ice loss is likely irreversible on multi-millennial timescales," said the University of Exeter report. A collapsing Greenland ice sheet raises the likelihood of sea-level rising and coastal flooding.
Antarctic ice sheet melting: A new report found that the Antarctic ice sheet is melting at a more accelerated rate than previously thought. "Warm ocean water is seeping beneath the ice sheet at its 'grounding line' — the point at which the ice rises from the seabed and starts to float — causing accelerated melting which could lead to a tipping point," said CNN. Even small changes in ocean temperature can push the sheet to melt further. "You get this kind of runaway feedback … where you can have a very sudden shift in how much melting is happening in these places," Alex Bradley, the lead author of the paper, said to CNN. "Our projections of sea level rise might be significant underestimates."
Biosphere tipping points
Accelerating extinctions: Human influence has greatly increased the rate of extinctions across the world, helping push the planet into its sixth mass extinction event, with almost a million plant and animal species currently at risk. Given "human activities such as land use change, overexploitation, climate change, pollution and introduction of invasive species, we have put our foot on the extinction accelerator," the University of Exeter report said, and the resulting threat to "our critical life-support systems is vastly underestimated." The Amazon rainforest as well as other rainforests are particularly at risk, suffering not only from human influence but also "unprecedented climate-driven disturbances such as increasing dry season length and intensity, more intense and frequent rainfall and temperature extremes," said the report. These extinctions have the potential to cause ecosystem collapses because species are largely interconnected. "We are increasing the risk of co-extinction," Sebesvari said to DW.
Dying coral reefs: Coral reefs are largely in danger due to climate change. Warming oceans are disrupting the delicate aquatic ecosystem causing bleaching, which is when "thermal stress causes corals to expel the symbiotic algae that provides them with food (resulting in a characteristic loss of color), and can result in death if it occurs frequently enough to prevent recovery," said the University of Exeter report. The threat is imminent and "more than 54 percent of the reef areas in the global ocean are experiencing bleaching-level heat stress," Derek Manzello, the coordinator of Coral Reef Watch, said to Al Jazeera. Coral reefs also hold a quarter of all marine life on Earth and their collapse could drastically alter the ecosystem.
Uninsurable future: The combination of the aforementioned tipping points means more and more places on Earth are becoming uninhabitable — and uninsurable. There has been a seven-fold increase in the amount of damage from natural disasters since the 1970s. Homes and businesses in disaster-prone areas are starting to see either extremely high insurance premiums or in some cases, little or no coverage as insurance companies pull out. Once home insurance becomes too expensive or unavailable, "people are left without an economic safety net when disasters strike," the report said. As the world gets closer to tipping past these points of no return, "we also lose some of our tools and options to deal with future disaster risk," Sebesvari said to Forbes.
Groundwater depletion: Much of the world's drinking water comes from underground reservoirs called aquifers. The bad news is that these aquifers are rapidly emptying, with 21 of the 37 largest aquifers losing water faster than they can be replenished. The water in the aquifers "has accumulated over thousands of years, and would equally take thousands of years to fully recharge," the report said, so these crucial reservoirs are "essentially a non-renewable resource." Approximately 2 billion people worldwide rely on groundwater as a primary source of drinking water, but most groundwater is used in agriculture. "We can no longer consider groundwater as a boundless source of easily accessible freshwater," the report said. And its increasing inaccessibility has "worrying implications."
Ocean and atmospheric tipping points
Unbearable heat: This year, the planet has broken numerous heat records. The warmer temperatures have caused intense heat waves and led to "an average of 500,000 excess deaths annually in the last two decades," the U.N. said. The heat also disproportionately affects more vulnerable populations. Along with its toll on humans, heat exacerbates a number of other ecological problems, including melting glaciers, extreme storms and extinctions. "The reality is that we are quickly approaching a tipping point past which people will not survive," the report said. As temperatures rise even higher, the heat's impact will get more extreme and harder to reverse.
Changing ocean currents: The extreme heat has also caused a meteoric rise in ocean temperatures which can lead to a shift in ocean currents. For example, the Atlantic Meridional Overturning Circulation (AMOC) may be disrupted in the future because the "surface waters in the northern North Atlantic may become less dense," said the University of Exeter report. Cold water is denser than warm water and the current works through different water temperatures rising and sinking. "AMOC may have weakened by around 15" over the past 50 years and may be at its weakest in 1,000 years." The current is crucial to maintain the climates of western and northern Europe.
Ocean deoxygenation: A new study published in the journal Nature Ecology & Evolution found that "lakes and reservoirs have experienced oxygen losses of 5.5% and 18.6% respectively in the past 45 years, and the oceans have dropped by 2%," said Popular Mechanics. While not previously considered a tipping point, scientists argue that it should be. Deoxygenated water can be detrimental to marine populations, leading to mass extinctions. It stems from warming temperatures, along with human factors like fertilizer runoff. "Failure to address aquatic deoxygenation will, ultimately, not only affect ecosystems but also economic activity, and society at a global level," said the lead author of the study, Kevin Rose, in a press release.
Space debris: The tipping points also extend to space, where floating detritus threatens both current satellites and our ability to put new ones into orbit. Satellites are crucial to our daily lives, from weather reporting and tracking natural disasters to navigating and communicating. "Each piece of debris becomes an obstacle in the orbital 'highway,' making it increasingly difficult for functional satellites to avoid collisions," the report said. "If we continue on the current trajectory, we risk sacrificing Earth's orbits and the opportunities they offer to society now and in the future."
