Food & Climate
For years, scientists and experts from international organizations and institutions have been warning against Land-use change, and an expert from the Food and Agriculture Organization of the United Nations (FAO) indicated that this was one of the causes of the Los Angeles wildfires. How was that?
Amy Duchelle of the Food and Agriculture Organization stresses that climate change plays a role in the increase of Los Angeles wildfires, but it is not the sole factor according a report seen by “Food & Climate” platform.
“Land-use change” is any way in which humans modify the natural landscape. Some of these changes are permanent destruction, such as urban expansion.
Other changes, such as cropland abandonment and forest restoration, may attempt to repair previous damage. It is a widespread phenomenon – humans have altered “about three-quarters of the Earth’s land surface” in the past millennium, a study said.
The reasons of Los Angeles wildfires
The UN’s Food and Agriculture Organization Senior Forestry Officer and Team Leader on Forests and Climate, Amy Duchelle, told “Vatican News” that there is “a changing scenario that’s making fire, much more intense.” Yet, climate change is not the only factor of wildfires. The way land is used and managed is also important. For example, urban infrastructures are edging more and more in nature and various ecosystems.
According to American government’s “USGS- science for a changing world”, The link between land use and the climate is complex. First, land cover–as shaped by land use practices–affects the global concentration of greenhouse gases.
Second, while land use change is an important driver of climate change, a changing climate can lead to changes in land use and land cover. For example, farmers might shift from their customary crops to crops that will have higher economic return under changing climatic conditions.
Higher temperatures affect mountain snowpack and vegetation cover as well as water needed for irrigation. The understanding of the interactions between climate and land use change is improving but continued scientific investigation is needed.
With increasing global surface temperatures, the possibility of more droughts and increased intensity of storms will likely occur.
As more water vapor is evaporated into the atmosphere it becomes fuel for more powerful storms to develop. More heat in the atmosphere and warmer ocean surface temperatures can lead to increased wind speeds in tropical storms. Rising sea levels expose higher locations not usually subjected to the power of the sea and to the erosive forces of waves and currents.
Current estimates of land-use change
Current estimates of land-use change may be capturing only one-quarter of its true extent across the world, research showed in 2021.
The paper, published in Nature Communications, revises previous estimates of how much humans change the Earth’s land surface – such as via the destruction of tropical rainforests.
It finds that, when accounting for multiple instances of change in the same place, 720,000 square kilometers of land surface has changed annually since 1960 – an area, the authors note, “about twice the size of Germany”.
Despite steadily increasing rates of land-use change over the latter half of the 20th century, the global rate has been decelerating since 2005. The authors attribute this slowdown to the 2007-08 financial crisis, which they hypothesise caused economic shifts in the global north that reverberated around the world.
When these “gross” changes are summed up, the total extent of land-use change between 1960 and 2019 is 43m km2 – just under one-third of the total land surface of the Earth.
Global land-use change nearly doubles when considering gross change, from 17% to 32% of the Earth’s land surface. And nearly two-thirds of this gross change is due to multiple-change events.
Studying land-use change in this way – as an accumulation of all the changes occurring over time, rather than as net change – can help better account for the greenhouse gas emissions associated with land use, Karina Winkler, the lead author of the study and a PhD candidate in land-system dynamics at the Karlsruhe Institute of Technology and Wageningen University, says.
Following the definitions used in the FAO’s annual surveys, the researchers separate out 6 categories of land use: urban areas, cropland, pasture, unmanaged grassland, forest and sparsely vegetated land. Several notable patterns jump out when looking at what types of change are occurring where, the authors say.
For example, about half of the single-change events – or nearly 20% of the total changes – occur due to agricultural expansion, such as deforestation. And 86% of the multiple-change events are agriculture-related, predominantly occurring in the global north and select rapidly growing economies.
In the Los Angeles wildfires, which may have been caused by land use change, it is estimated that more than 10,000 structures were destroyed or damaged in the four fires—Palisade, Eaton, Outo, and Hurst —with 25 people confirmed dead, more than a dozen missing, and tens of thousands forced to evacuate their homes.