Global warming, Climate change

The science | ‘The scientific consensus on global warming has hardened, making blanket opposition harder to maintain,’ (‘Lexington–Salting the Earth’, The Economist 27th January 2018, p.40). Earth is warming because carbon dioxide and other greenhouse gases are accumulating in the atmosphere, shifting the balance of energy arriving from the sun and flowing back out into space (‘Free exchange–a hot mess’, The Economist 27th April 2019, p.64).

Data | ‘The concentration of carbon dioxide in the atmosphere has risen by 15% since 1994 and the first global climate-change treaty, the United Nations Framework Convention on Climate Change. The average global temperature, relative to the norm for 1951-80, has gone up by about 0.5°C over that period. And in 2018 annual emissions reached their highest level ever. To have a good chance of stopping global temperatures rising more than 1.5°C relative to the pre-industrial norm, by 2030 annual greenhouse-gas emissions must fall by almost half, relative to levels in 2010, according to the Intergovernmental Panel on Climate Change. They almost certainly will not. A much warmer and more hostile climate might yet be avoided, however, through geoengineering: tinkering with climate processes to reduce the global temperature. (The possibilities are described at length in “The Planet Remade” by Oliver Morton, a journalist on this newspaper.) The longer climate targets are missed, the more likely geoengineering is to be used—and the more urgent it is that governments understand its tricky political economy,’ (‘Free exchange–a hot mess’, The Economist 27th April 2019, p.64).

Emissions | ‘Industries like iron and steel, cement and power-generation, which produce about half of all energy-related CO2 emissions yet grumble over carbon-pricing schemes and renewable-energy mandates intended to change their behaviour. A favourite excuse for foot-dragging is that onerous regulation risks “carbon leakage” to countries with laxer emissions rules,’ (‘Schumpeter, The seven ages of climate man’, The Economist 15th May 2019, p.63).

Climate change & Wine | ‘Research in recent years suggests that, in a warmer world, grapes will cope better at higher latitudes and elevations. A study published [April 2015] in Nature Climate Change, a journal, found that grapes across France are now harvested two weeks earlier than they were 500 years ago. This trend could mean that wine gets worse, as it did after Europe’s heatwave in 2003. Grapes exposed to too much sun become sweeter and less acidic; eventually, they become raisins. Some spots, such as California’s Napa Valley, may get too hot for vines altogether. This will squeeze the juice out of an industry that generates more than $1 billion a year in taxes in America,’ (‘Desert wines’, The Economist 14th May 2016, p.28).

‘In the past 150 years, the concentration of carbon dioxide in the atmosphere has risen from 280 parts per million (ppm) to 410 ppm. For farmers this is mixed news. Any change in familiar weather patterns caused by the atmospheric warming this rise is bringing is bound to be disruptive. But more carbon dioxide means more fuel for photosynthesis and therefore enhanced growth—sometimes by as much as 40%. And for those in temperate zones, rising temperatures may bring milder weather and a longer growing season. (In the tropics the effects are not so likely to be benign.) What is not clear, though, and not much investigated, is how rising CO2 levels will affect the relation between crops and the diseases that affect them,’ (‘Blocking the road to rusty death’, The Economist 20th April 2019, p.69).

Rodale study: Plants absorb carbon dioxide from the air and can put it more or less permanently into the soil under the right conditions. In a 23-year side-by-side comparison, the carbon levels of organic soils increased 15 to 28 percent while there was little change in the non-organic systems, according to the Rodale Institute Farming Systems Trials conducted in the U.S. state of Pennsylvania. If just 10,000 medium-sized farms in the U.S. converted to organic production, they would store so much carbon in the soil that it would be equivalent to taking 1,174,400 cars off the road, Rodale reported in 2003.

See also | Air travel & carbon emissions. | The Anthropocene. | Bill McKibben. | Carbon pricing. | Chlorofluorocarbons. | Crops & Climate Change. | Deforestation. | El Niño. | Energy efficiency. |  Greenhouse-gas emissions. Hurricanes. | Intergovernmental Panel on Climate Change. | Kyoto Protocol 1997. | Methane. | Montreal Protocol 1987. | Ocean acidification. | Ozone layer. | Paris Accord 2015. | Rio Summit 1992. | Solar cycles