carbon

Beginning in the 1940s, the “green revolution” increased crop yields around the globe through seed hybrids, increased irrigation and new fertilizers and pesticides. The result was “agricultural intensification,” getting more grain from each acre of land. While the increase in productivity is unquestioned, drawbacks exist as well — negative environmental and health consequences from pesticide use, increased water demand, reductions in biodiversity and increased vulnerability to future famines.

Because climate change is a global phenomenon and its potential effects diverse, understanding the economic impacts is highly complex. Agriculture, fishing, migration, health and tourism could all be affected; in many ways the impacts are likely to be negative, but some could be positive.

Just as nations have different levels of population, industrial and agricultural production, income and education, so they have varied environmental impacts. Such impacts aren’t stable over time: Countries’ use of resources and generation of wastes often rises as production grows, then may fall as cleaner technologies and better environmental practices come into use. While this trend has been theorized, empirical evidence has been mixed.

By 2030 electric usage in the United States is projected to grow by more than 30%. Fossil fuels and nuclear power currently produce the lion’s share of our electricity, but in a carbon-constrained world, renewables will have a greater role to play.

Efforts to limit climate change generally focus on reducing carbon dioxide emissions caused by burning fossil fuels. However, another byproduct of fossil fuel combustion is black carbon, a major component of soot. Sources include diesel truck and car engines as well as wood fires, kilns, and stoves. Particles of black carbon in the atmosphere absorb sunlight and can have significant effects on the temperature, as do ozone, methane and other chemicals.