homehome Home chatchat Notifications


We've changed a third of the Earth's land surface in less than 60 years

Hurray, we did it... wait, that's bad?

Fermin Koop
May 12, 2021 @ 10:47 pm

share Share

A third of the global land surface, or 43 million squared kilometers, has been subject to change from 1960 to 2019, driven by an expansion in agriculture and cattle ranching, a new study shows. This means that on average a land area of about twice the size of Germany (720,000 squared kilometers) has been altered every year since 1960.

Image credit: CIFOR

“Land-use change” refers to ways in which humans alter the natural landscape. This can be permanent destruction, such as urban expansion, or just temporary. Some changes, such as forest restoration or regeneration, may attempt to repair previous damage. Overall, it’s a widespread phenomenon, previous studies have shown. But we weren’t expecting it to be this widespread.

Land use is usually measured by high-resolution satellite imagery and by large-scale statistical surveys. But each method has its own shortcomings when assessing land-use change. Satellites can capture land use in high detail, but their records only extend back a few decades, while statistical methods go further back in time but at a worse resolution.

Little work has been done to combine both approaches – until now. Karina Winkler, a physical geographer at Wageningen University & Research in the Netherlands, and her colleagues brought together more than 20 satellite land-use products and long-term surveys. The resulting dataset captures changes in land use with a 1km resolution.

But not all land-use change is permanent. So instead of looking at “net” changes that only capture the overall transformation of an area, the dataset captures places where land use has changed multiple times, such as rotation between cropland and pasture. When this is added, the extent of land-use change is really massive.

The map below, done by the researchers shows where both single-change (yellow shading) and multiple-change (red) events are occurring around the world. Instances of multiple-change events are dominant across Europe, India, and the US, while single-change events are widespread across South America, China, and south-east Asia.

Image credit: The researchers

Land-use change

For their study, Winkler and her team established six categories of land use, following the definitions used by the Food and Agriculture Organization (FAO): urban areas, cropland, pasture, unmanaged grassland, forest, and sparsely vegetated land. Notable patterns jump out when looking at what types of change are occurring where.

For example, about half of the single-change events (or nearly 20% of the total changes) happen because of agricultural expansion, such as deforestation. And 86% of the multiple-change events are agriculture-related, predominantly happening in the global north and select rapidly growing economies.

Averaged globally, land-use change steadily increased for nearly half a century. But, in 2005, there was a “rather abrupt change” in this trend and land-use change began decelerating worldwide, the authors found. This is most evident in Africa, South America, and regions of Subtropics and Tropics and linked to market developments.

The charts below show the differences in land-use change rates in six geographical regions, as well as the worldwide average. The global rates of change are defined by an acceleration period from 1960 to the early 2000s, followed by deceleration since about 2005. Land-use change is responsive to “socio-economic developments,” the authors write.

Image credit: The researchers

Almost one-quarter of total human-caused greenhouse gas emissions between 2007 and 2016 were due to agriculture, forestry, and other land use, according to the Intergovernmental Panel on Climate Change (IPCC). This falls just behind electricity and heat production as the world’s second-largest contributor to global emissions.

But if conserved properly land can actually help bring down emissions, acting as a sink of greenhouse gases – for example with the carbon absorbed by the forests. The balance of sources and sinks through land-use change, the IPCC says, is a “key source of uncertainty” in considering the future of the land carbon cycle.

The study was published in the journal Nature Communications.

share Share

A London Dentist Just Cracked a Geometric Code in Leonardo’s Vitruvian Man

A hidden triangle in the vitruvian man could finally explain one of da Vinci's greatest works.

Glass bottles shed up to 50 times more microplastics into drinks than plastic or cans -- and the paint on the cap may be to blame

Glass bottles may surprisingly release more plastic particles than plastic ones.

The Story Behind This Female Pharaoh's Broken Statues Is Way Weirder Than We Thought

New study reveals the ancient Egyptian's odd way of retiring a pharaoh.

China Resurrected an Abandoned Soviet 'Sea Monster' That's Part Airplane, Part Hovercraft

The Soviet Union's wildest aircraft just got a second life in China.

This Shark Expert Has Spent Decades Studying Attacks and Says We’ve Been Afraid for the Wrong Reasons

The cold truth about shark attacks and why you’re safer than you think.

A Rocket Carried Cannabis Seeds and 166 Human Remains into Space But Their Capsule Never Made It Back

The spacecraft crashed into the Pacific Ocean after a parachute failure, ending a bold experiment in space biology and memorial spaceflight.

Ancient ‘Zombie’ Fungus Trapped in Amber Shows Mind Control Began in the Age of the Dinosaurs

The zombie fungus from the age of the dinosaurs.

Your browser lets websites track you even without cookies

Most users don't even know this type of surveillance exists.

What's Seasonal Body Image Dissatisfaction and How Not to Fall into Its Trap

This season doesn’t have to be about comparison or self-criticism.

Why a 20-Minute Nap Could Be Key to Unlocking 'Eureka!' Moments Like Salvador Dalí

A 20-minute nap can boost your chances of a creative breakthrough, according to new research.