Carl Sagan first introduced the idea of a “nuclear winter”, which helped to end the cold war. The smoke from fires started by bombs would absorb so much sun the earth wold grow cold, dry, and dark, killing plants on land and in the water world-wide, jeopardizing the whole human race.
New findings indicate that even a small regional nuclear war could have the same effect globally. Widespread death would result far from the initial conflict.
Excerpts from Robock, Alan et al., January 2010 Scientific American “LOCAL, NUCLEAR WAR. Worry has focused on the U.S. versus Russia, but a regional nuclear war between India and Pakistan could blot out the sun, starving much of the human race“.
Original paper: Robok, A. 19 April 2007. Climatic consequences of regional nuclear conflicts. Atmospheric Chemistry and Physics.
Alan Robock and Woen Brian Toon: “Some people think that the nuclear winter theory developed in the 1980s was discredited. And they may therefore raise their eyebrows at our new assertion that a regional nuclear war, like one between India and Pakistan, could also devastate agriculture worldwide. But the original theory was thoroughly validated. The science behind it was supported by investigations from the National Academy of Sciences, by studies sponsored within the U.S. military, and by the International Council of Scientific Unions, which included representatives from 74 national academies of science and other scientific bodies.”
- Nuclear bombs dropped on cities and industrial areas in a fight between India and Pakistan would start firestorms that would put massive amounts of smoke into the upper atmosphere.
- The particles would remain there for years, blocking the sun, making the earth’s surface cold, dark and dry. Agricultural collapse and mass starvation could follow. Hence, global cooling could result from a regional war, not just a conflict between the U.S. and Russia.
- Cooling scenarios are based on computer models. But observations of volcanic eruptions, forest fire smoke and other phenomena provide confidence that the models are correct.
HUMAN TOLL. An all-out nuclear war between India and Pakistan could slaughter people locally and lead to more deaths across the planet.
- 20 million people in the region could die from direct bomb blasts and subsequent fire and radiation.
- 1 billion people worldwide with marginal food supplies today could die of starvation because of ensuing agricultural collapse.
Excerpts from: Mills, M.J. 8 Apr 2008. Massive global ozone loss predicted following regional nuclear conflict. Proceedings of the National Academy of Sciences vol 105:14:5307-5312.
If war broke out between 2 countries and 100 Hiroshima-sized bombs were dropped on cities, the smoke from these fires would result in a giant ozone hole that would last for 5 years. The worst effects would be the northern high latitudes, with a 50-70% ozone loss (and 20% globally, 25-45% mid-latitude).
The resulting increase in UV radiation would kill or harm plants and animals resulting in serious consequences for human health.
“The ozone losses predicted here are significantly greater than previous “nuclear winter/UV spring” calculations… Our results point to previously unrecognized mechanisms for stratospheric ozone depletion”.
The absorption of sunlight by the stratospheric soot produces a global average surface cooling of 1.25°C persisting for several years and large reductions in precipitation associated with the Asian summer monsoon and other disruptions to the global climate system.
Depletion of the ozone column relative to normal conditions may impact living organisms, which are usually adapted to local UV radiation levels. Increased UV radiation is largely detrimental, damaging terrestrial and oceanic plants and producing skin cancer, ocular damage, and other health effects in humans and animals (12). Conclusive evidence shows that increased UV-B radiation damages aquatic ecosystems, including amphibians, shrimp, fish, and phytoplankton (13). The effects of sunlight on the biota are quantified as a product of the sun’s spectrum at the Earth’s surface and the action spectra for biologically damaging processes, such as erythema, carcinogenesis, and photoinhibition. An analysis of biological sensitivity to UV spectral changes concluded that a 40% ozone column depletion at 45°N – as computed here – would increase DNA damage (believed related to carcinogenesis) by 213%, and plant damage (e.g., photoinhibition) by 132% relative to normal conditions.
The global-scale ozone reductions predicted here for relatively small injections of sooty smoke into the upper troposphere and lower stratosphere indicate an unexpected sensitivity associated with such perturbations, and suggest that certain events-such as regional nuclear conflicts, or geo-engineering schemes based on absorbing carbonaceous aerosols-might pose an unprecedented hazard to the biosphere worldwide. Our regional nuclear scenario involves <0.1% of the yield of nuclear weapons that currently exist. The current build-up of arsenals in an increasing number of states suggests scenarios in the next few decades that are even more extreme. The potential hazard to global ozone, and hence terrestrial biota, deserves careful analysis by governments worldwide advised by a broad section of the scientific community.
Other articles on nuclear winter
Charles Q. Choi. 22 Feb 2011. Small Nuclear War Could Reverse Global Warming for Years: Regional war could spark “unprecedented climate change,” experts predict. National Geographic News
Tim Murray. 9 Dec 2011. Recipe for Nuclear Winter. candobetter.net
2 July 2012. War-Related Climate Change Would Reduce Substantially Reduce Crop Yields. ScienceDaily.