Thanks to Carolyn Kormann for this reminder of the impact our diet has on the future of the planet:
In the Amazon, or in the parts of the Amazon that people have mowed down and converted into grazing pasture, the average abattoir-bound cow has nearly three acres to himself. Nice for the cow, perhaps, but senseless and dangerous in every other way. Every year, on average, tropical deforestation adds ten to fifteen per cent of global greenhouse emissions. Of this amount, around half happens in South America; deforestation in the Amazon recently increased. If the rate continues, scientists have found, it could lengthen the forest’s dry season, triggering even greater warming and drying, killing trees in the nearby (still intact) forest, and eventually causing mass tree mortality and an entire ecosystem shift—from rainforest to savannah. The tipping point in the Amazon would be a rate of twenty-twenty-five per cent deforestation—fifteen to seventeen per cent is already gone. “If you exceed the threshold,” Carlos Nobre, a Brazilian climate and tropical-forest expert, told me, “fifty to sixty per cent of the forest could be gone over three to five decades.”
An urgent new report from the United Nations’ Intergovernmental Panel on Climate Change (I.P.C.C.), published this morning in Geneva, Switzerland, highlights “what has been true all along,” Deborah Lawrence, an environmental-sciences professor and tropical-ecosystem expert at the University of Virginia, said. “We cannot make our climate goals without stopping deforestation and better managing agriculture.” In the past, I.P.C.C. reports focussed on what various energy futures will mean for the atmosphere. How much will we reduce the use of fossil fuels, by when, and what might that look like for all of earth’s systems? In this case, however, the panel focussed exclusively on land—how people’s unsustainable use of land is dramatically contributing to climate change. According to the report’s findings, land use is responsible for twenty-three per cent of global greenhouse-gas emissions—half from carbon dioxide emitted through deforestation, half from agriculture. (If pre- and post-production activities in the global food system are included, the emissions are estimated to account for as much as thirty-seven per cent of total human-caused greenhouse-gas emissions.) In turn, climate change is hastening land degradation, destabilizing the food supply, and harming the livelihoods of hundreds of millions of people. “Climate change creates additional stresses on land, exacerbating existing risks to livelihoods, biodiversity, human and ecosystem health, infrastructure, and food systems,” the report’s summary for policy makers states. “Some regions will face higher risks, while some regions will face risks previously not anticipated.”
Since the industrial revolution, the overland air temperature has risen by about 1.53 degrees Celsius, or nearly three degrees Fahrenheit—almost double the average increase over the land and sea combined. Around the world, there have been more frequent, intense, and longer-lasting heat waves, and changing precipitation patterns—heavier bouts of rain over all, and more frequent and intense droughts in some regions, including the Mediterranean, many parts of South America, much of Africa, and northeastern and western parts of Asia. Climate change has increased risks from water scarcity, soil erosion, vegetation loss, wildfire damage, permafrost thawing, coastal dissolution, and tropical crop decline. In the Global South, climate change has caused the yields of some crops, such as maize and wheat, to decline, and lowered animal-growth rates and productivity in African pastoral systems. Interviews and community surveys with indigenous groups in the African drylands and high-alpine regions of Asia and South America also detail the ways that changes in the regional climate have further challenged their food security. As of 2015, five hundred million people lived in areas that were affected by desertification…
Read the whole article here.