Unsustainable land use and greenhouse gas emissions are delivering a one-two punch to natural ecosystems that are key to the fight against global climate change. And without sweeping transformations to food production and land management, the world stands no chance of staving off catastrophic planetary warming.
That’s according to a dire new United Nations assessment of the complex relationship between terrestrial landscapes and climate change. The report from the Intergovernmental Panel on Climate Change, or IPCC, the leading U.N. body of researchers studying human-caused global warming, warns that human exploitation of land poses a serious threat to the food supply, natural resources and wildlife.
Climate change has already taken a toll on natural environments by fueling drought, extreme weather, wildfires, coastal erosion and the thawing of Arctic permafrost. And those risks are forecast to become “increasingly severe with increasing temperatures,” according to the findings. At the same time, humans have altered as much as 76% of the planet’s ice-free land. Agriculture, deforestation, urban development and other types of land use account for approximately 23% of total human greenhouse gas emissions and have left swaths of the global landscape degraded.
As the report details, land can be a major contributor to climate change. It can also be a tool for solving it. Earth’s natural landscapes continue to act as a buffer against warming, absorbing 29% of all carbon dioxide emissions, the report found.
Humans and the global economy are getting “a free subsidy from nature,” Louis Verchot, a report author and land-use expert at the Colombia-based International Center for Tropical Agriculture, told reporters during a call Wednesday. But he stressed that it won’t last forever.
“This additional gift from nature is limited,” he warned. “If we continue to degrade ecosystems, if we continue to convert natural ecosystems, to deforest, to destroy our soils, we’re going to lose this natural subsidy that’s protecting us, in part, from ourselves and from the damage we’re creating as we pump these greenhouse gases into the atmosphere.”
Every 30 seconds in the U.S., a natural area the size of a football field is lost to development, according to a separate study released this week and commissioned by the left-leaning Center for American Progress.
The 1,300-page IPCC report ― co-authored by more than 100 experts from 53 countries and released Thursday following a summit in Geneva, Switzerland ― is the latest in a series of scientific assessments over the last year that have made one thing strikingly clear: The world is rapidly running out of time to keep global temperatures from reaching 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels ― the goal of the 2015 Paris climate agreement.
In October, the IPCC concluded that world governments must cut global emissions roughly in half by 2030 to keep the global mean temperature from hitting the 1.5 degree mark, at which point climate-related damages will cost an estimated $54 trillion. The planet has already warmed 1.1 degrees Celsius (just shy of 2 degrees Fahrenheit).
Still, President Donald Trump continues to downplay the threat and defend his 2017 decision to withdraw the U.S from the Paris Agreement. His administration has worked to gut major Obama-era policies that sought to rein in planet-warming emissions, revoked land protections and forged ahead with its fossil fuel-centric “energy dominance” agenda.
After decades of inaction, mitigating the threat requires more than transforming the global energy sector and phasing out fossil fuels. It demands slashing emissions from all areas of society, including land use and food production, the U.N. report finds.
“There are a lot of actions that we can take now,” report author Pamela McElwee, an associate ecology professor at Rutgers University, said during Wednesday’s press call. “They’re available to us now. We don’t have to wait for some sort of new technological innovation. What some of these solutions do require is attention, financial support, enabling environments. They’re just not scaled up to the degree that they need to be right now.”
Alternatives for offsetting greenhouse gas emissions include preserving and restoring forests, peatlands and coastal wetlands; limiting land degradation through sustainable management; and implementing farming practices that boost organic carbon content in the soil. The report also highlights opportunities to reduce emissions and better protect land by cutting food waste ― up to 30% of all food produced is lost or wasted ― and moving toward plant-based diets.
Other options would no doubt offset large amounts of CO₂ emissions but require additional land conversion and compete with global food production. For example, the report found that large-scale planting of new forests in treeless areas could potentially increase food prices by up to 80% and put 80 million to 300 million people at risk of undernourishment, according to McElwee.
“That’s a very serious trade-off,” she said. “Let’s understand those trade-offs now and think about them, but also think about things that maybe would help us avoid those trade-offs.”
The report is yet another sobering wake-up call about the magnitude of the crisis and what it will take to solve it.
In a statement Thursday, Jennifer Tabola, director of global climate strategy at The Nature Conservancy, called on communities, world leaders and corporations to take urgent action to combat the over-exploitation of the Earth.
“As with climate change in general, we have a choice: Do we balance the needs of human development and nature, or do we sleepwalk into a future of failing farmlands, eroding soil, collapsing ecosystems and dwindling food resources?” she said.
In addition to its climate assessment late last year, the U.N. released a report in May that found that up to 1 million species of land and marine animals are at risk of extinction due to human actions. And in June, Philip Alston, the U.N. special rapporteur on extreme poverty and human rights, sounded the alarm that the world is headed for a “climate apartheid” that could push an additional 120 million people into poverty by 2030.