Skip to navigation

Skip to main content


October 2019, Volume 25, Number 4


The Intergovernmental Panel on Climate Change released a report in August 2019 warning that the over-exploitation of farm land and water resources threatens the world's food supply. The report estimated that 500 million people currently live in places that are turning into desert, and that soil is being lost between 10 and 100 times faster than it is being created.

The IPCC identified four pillars of food security: availability or yield and production, access or prices and incomes and the ability to obtain food; utilization or nutrition and cooking; and stability or disruptions that affect availability. Climate change can affect all four pillars, reducing yields in the tropics, raising food prices, reducing the nutritive value of some foods and disrupting the availability of food.

Climate change threatens to make desertification, flooding, and soil loss problems worse, and could increase migration pressures. Rising levels of carbon dioxide and higher temperatures increase food production in some areas that are currently too cold for crop production, but not enough to offset the loss of food production from land lost to erosion, desertification and rising seas.

The IPCC report urges more research to increase the productivity of farm land and policies to reduce food waste. The IPCC also wants people to shift their diets from meat to plant-based foods. A third of the food produced is believed to be lost or wasted.

The IPCC estimates that farming and other land uses account for nearly a quarter of greenhouse-gas emissions, while half of methane emissions are from cattle and rice field. The report criticizes the conversion of rain forest and the draining of wet lands to create more farm land, saying that creating more farm land via deforestation and drainage increases carbon emissions by five gigatons a year (the fossil fuel industry emitted 37 gigatons in 2018).

The IPCC in September 2019 warned that up to 700 million people living in coastal communities are threatened by rising sea levels as glaciers melt. The IPCC noted that the warming atmosphere can create patches of warmer seas that can disrupt fisheries, such as the summer 2019 warmer water patch between Alaska and Hawaii.

US. With human-caused emissions considered to be the primary driver of climate change, mostly due to carbon-dioxide emissions from generating electricity and operating factories, planes and cars, most of the Democrats running for president have endorsed a Green New Deal, an effort to reduce US carbon emissions. Two Democrats, Jay Inslee and Tom Steyer, made combating climate change the central purpose of their campaigns.

President Trump withdrew the US from the 2015 Paris Agreement that committed countries to take action to limit the increase in global temperatures to 2C or 3.6F above pre-industrial times. In 2019, average global temperatures were 1.1C above preindustrial levels.

The leading contenders to be the Democratic presidential candidate unveiled plans to spending trillions over the next decade to reduce or eliminate US carbon emissions by 2030. Most would require buildings and cars to have zero emissions by 2030.

Stewart and Lynda Resnick, owners of Fiji Water, Pom Wonderful, Wonderful Pistachios and Teleflora, donated $750 million to Caltech for climate research. Resnick-owned businesses are believed to be the largest single consumer of water in the US.

Warming. The summer of 2019 saw record temperatures in Europe, the melting of ice sheets in Greenland, and thawing permafrost in Siberia. All of the glaciers in Iceland are melting, which is pushing up land that had previously been compacted by the weight of glacial ice. A heat wave that originated in the Sahara Desert moved to Greenland in early August 2019, where it speeded the melting of glaciers.

Paris reached 41C or 105F July 24, 2019. The heat and lower rainfall led to water rationing in most of France and reduced crop yields, especially for corn. During a 2003 heat wave, some 15,000 people died in France.

The Arctic is warming faster than other regions. Permafrost covers two-thirds of Russia, with the frozen ground sometimes a mile deep. In Russia's Yakutia district, which has 20 percent of Russia's area and where over 90 percent of the land is permafrost, warmer winters and longer summers are thawing the frozen earth. Wildfires are more frequent and larger, but the difficult terrain means that fires are generally allowed to burn themselves out.

Water. Fresh water may become increasingly scarce, especially in fast-growing areas such as South Asia. The UN says that global spending to provide fresh water should rise from less than $50 billion a year to $200 billion a year to ensure that all people have access to safe water.

The World Resources Institute in August 2019 reported that 17 countries are under extremely high water stress, including India and Iran, meaning that they use almost all of the fresh water available to them. New Delhi is the largest city that uses all of the fresh water available to it, while New York has an ample supply of fresh water.

Dead whales, seals and sea lions on the east and west coasts of the US in summer 2019 were blamed on warming waters. Over 100 dead gray whales were found on the US west coast in summer 2019, the most in two decades. Warmer water has fewer nutrients, and is often associated with more animal deaths; there are also more algae blooms that can lead to domoic acid poisoning. The average temperature of the Pacific Ocean off San Diego rose to 65F in summer 2019, and was 55F in northern California.

Mexico's Yucatan Peninsula was plagued by rotting seaweed known as sargassum in summer 2019. Tourism employs about four million Mexicans and generates $100 billion a year, which about eight percent of Mexico's GDP. The sargassum is discouraging some visitors to beach resorts.

Ocean currents generate the Sargasso Sea in the central Atlantic Ocean. The sargassum began to move toward the Caribbean in 2011, and the amount reaching tourist beaches began to increase. Some scientists believe that sargassum growth is fueled by runoff from nitrogen fertilizers.

Chinese firms are logging along the Trans-Siberian Railway, reacting to limits on logging in China to protect the environment. Some Russians fear that the Chinese will deplete Russian forests, as Russian trees are turned into lumber and sent to China. Russian lumber exports to China were $3.5 billion in 2018; most of the Russian lumber is turned into furniture and flooring in China and re-exported.

Russia leads the world in forest depletion, losing 16.3 million acres in 2018, compared to 9.1 million acres a year lost in the Amazon. Russia's taiga or boreal forest is allowed to grow back, while land cleared in the Amazon is often farmed, with pasture for cows and fields for soybeans replacing jungle.

Fires. The number of fires burning in the Amazon during the cooler and drier summer months of June through September almost doubled in 2019 from the previous summer, including 26,000 in August 2019. French President Emmanuel Macron called the Amazon the earth's lungs in August 2019 and pledged support for putting out Amazon fires, but the Brazilian President Jair Bolsonaro rejected the aid, saying that Macron was trying to protect French farmers.

Bolsonaro, elected in 2018, reduced efforts to limit deforestation in the Amazon, which encouraged farmers who want to plant crops to clear forests by setting fires. Several European countries contributed to an Amazon protection fund to preserve the Amazon to slow climate change, and threatened to withhold contributions. Bolsonaro ignored their threat and said that the Amazon belongs to Brazil, not Europe.

The Amazon has 20 percent of the world's fresh water and its vegetation absorbs a high share of the world's climate-warming carbon dioxide. One estimate is that the Amazon's plant life stores an estimated 100 billion tons of carbon. All of the world's coal-burning power plants emit 15 billion tons of carbon a year.

Bolsonaro reduced the budget of the environmental protection agency and limited its authority to levy fines and destroy the equipment of illegal loggers, miners and farmers, who often set fires during the dry season to clear land for their activities. Many fires are set over land disputes, and over 95 percent of fines assessed for illegal activities in the Amazon are contested, so that many are reduced or not paid.

About 20 percent of the Amazon has been cleared. When a quarter to a third of the rain forest is gone, a process known as die back could occur, meaning that the rain forest could erode into savannah that emits rather than absorbs greenhouse gases. Repeated fires make the rain forest less likely to regrow the same plants, since each fire allows grasses to replace some of the original undergrowth.

Healthy rain forests absorb rain and ground water and sweat it back into the atmosphere as moisture, seeding more rain. Rain forests that have been thinned by burning give off less moisture, which decreases rainfall and contribute to die back as drier rainforests burn hotter and more extensively.

Brazil's Cerrado accounts for about 60 percent of Brazil's soybean production, compared with less than five percent of Brazil's soybeans from the Amazon. Environmental advocates want foreign buyers of Brazil's soybeans to refuse to purchase those produced by clearing savannah in the Cerrado or jungle in the Amazon. The Chinese companies that buy most of Brazil's soy do not check on where the soybeans were produced.

Australia is the driest continent, and rising temperatures combined with lower rainfall is making bush fires more common and intense. With almost all of New South Wales in drought, the fire season is expected to be worse in 2019.

Climate Change and Land. 2019. IPCC.