Climate change is occurring which, if allowed to continue, will result in rapid increase of global temperatures. Rapid in terms of normal geologic time, over centuries rather than over millions of year. The change is being driven by human activities, emission of massive amounts of carbon dioxide, methane, and black carbon. Global civilization, both physically and economically, is structured in ways which require emissions of pollutants at levels which greatly exceed the levels rationally necessary for maximization of global human welfare.
Unchecked, global climate change will result in a large increase in the global temperature over the next few centuries, 10 degrees or more centigrade. Patterns of weather, temperature and precipitation, will change radically producing great stress on ecological and economic systems, particularly infrastructure near sea level. Billions of people live with the coastal zones that would be flooded by anticipated rises in sea level.
Due to slowness of heating of the world's oceans, there is a considerable time lag, decades or more, between increased emissions and the environmental consequences. Thus public awareness, as formed by direct experience, lags scientific foresight, making political mobilization around this issue difficult. The situation is complicated by capitalist forces, working against their own long-term interests view as a whole, which for short term profits though production and use of hydrocarbons attempt to influence the debate by confusing the issue.
Sounding the alarm
Bill McKibben, a writer for The New Yorker which was read by opinion leaders in New York City, New England, and the United States introduced the public to the crisis in The End of Nature. There were earlier books on the problem, but McKibben's work moved the issue onto the public agenda.
Solving the problem
"Gobal warming is not about overconsumption, morality, ideology or capitalism. It is largely the result of human beings generating energy by burning hydrocarbons and coal."
Global average temperature increased 0.6ºC ± 0.2ºC over the 20th century and is increasing more rapidly now.
Previous climate change
As a broad trend, the Earth's climate alternates between greenhouse periods and icehouse periods. Icehouse periods are those during which large continental ice sheets exist (eg. glaciers), and there is year-round sea ice at high latitudes. Greenhouse periods are periods during which those phenomena are absent. We are presently in an icehouse period. The problem with the present people-caused global warming is not the simple temperature rise that it will cause – the Earth has supported abundant life during past greenhouse periods that were 10ºC warmer than today – the problem is the speed at which we are raising the temperature. In the past, a warming of 5ºC in a few thousand years was unusually rapid; we may see a 5ºC rise within the next 100 years. This does not give living species time to adapt, and even human society will experience large costs in adapting.
Over the last 600 million years, there have been five icehouse periods separated by four greenhouse periods. Each period lasts 50-100 million years. During these periods there are also shorter-term fluctuations. Hyperthermals are short-term periods of exceptional warmth. An example of a hyperthermal is the Pliestocene-Eocene thermal maximum (PETM), which occured around ___ million years ago. During the PETM, global average temperature rose about 5ºC in 10,000 years, probably from the greenhouse effect of a sudden rise in atmospheric CO2. It is thought that the additional injection of carbon (C) into the atmosphere was less than 3,000 Gigatonnes (GT, 109 metric tons); this resulted in somewhat less than a doubling of the concentration of CO2 in the atmosphere. Considerable acidification of the ocean occurred along with these events. Over the next 150,000 years, the temperature reverted to its pre-PETM level. 150,000 years is the typical time scale for the deep sequestration of carbon which is performed by silicate rock weathering and oceanic deposition. Hyperthermals such as the PETM, with their rapid CO2 injection and temperature rise, are the closest known analogue to the present anthropogenic carbon release. Note, however, that the PETM was still gradual compared to what we are doing.
More recently within the present icehouse period, from the last glaciation around 20 thousand years ago (when ice sheets extended much farther South than they do now) to the present interglacial sub-period which commenced some 10 thousand years ago, global temperature rose about 5ºC. Associated with this was a sea-level rise of about 120 metres.
Current climate models predict that a doubling of atmospheric CO2 concentration results in about a 3ºC rise in global temperature.
- R Caballero and P Lynch, 2011. `Climate Modelling and Deep - Time Climate Change', in Trevor Hodkinson et al. Climate Change, Ecology and Systematics.
- Barrie Pittock, 2005. Climate Change.
- Pages 8 to 20, The End of Nature, Bill McKibben, Random House (1989), hardcover, 226 pages, ISBN-10: 0394576012
- "Climate change eroding Arctic seasons" article by Bob Weber in the Halifax Chronicle Herald from The Canadian Press March 10, 2013 Cite error: Invalid
<ref>tag; name "" defined multiple times with different content
- A communist governed globe would still face global warming and its ancillary issues.
- Matthew C. Nisbet. Nature’s Prophet: Bill McKibben as Journalist, Public Intellectual and Activist. Discussion Paper Series #D-78. Joan Shorenstein Center on the Press, Politics and Public Policy, School of Communication and the Center for Social Media American University. URL accessed on March 8, 2013.
- "The God Species by Mark Lynas - review: A brave look at the environment" book review by Peter Forbes in The Guardian, Wednesday 20 July 2011
- This paragraph, as it exists in 2014, is based on information in Caballero and Lynch, pp 49, 54.
- Periods, PETM, and analogousness are sourced from R Caballero and P Lynch (2011: 54, 58).
- Pittock, p 4.
- Caballero and Lynch, 58.