A New Greenhouse Gas
Readers will be familiar with the idea that burning fossil fuels releases carbon dioxide, which in turn absorbs infrared radiation, and which is then re-emitted as heat in the atmosphere. This is the greenhouse effect and the source underlying the worry about global warming and climate change.
CO2 is not the only greenhouse gas. Others include water vapor, methane, nitrous oxide, ozone, and a few other gaseous compounds. All are regulated by the agreement signed by most countries in Kyoto that went into effect in 2005. The commitment ends in 2012, and there is considerable anxiety that the planet’s multifarious nations will not come to terms on a renewal.
A recent publication raises a new worry—halogenated organic compounds used for general anesthesia (British Journal of Anaesthesia 105:6 [December 6, 2010 ], 760–766.) Isoflurane, desflurane, and sevoflurane are widely used as inhalation anesthetics in surgical procedures in both humans and animals. The authors report that the infrared absorption properties of these gases make them exceptionally effective at radiative forcing of climate change.
One could argue (and no doubt some will) that anesthetics are present in the atmosphere at too low a concentration to worry about. However, the authors estimate worldwide medical use of these agents and conclude that their contribution to global warming is the same as one coal-fired power plant or 1 million passenger cars.
Should you worry about this when you are slowly slipping from consciousness prior to a surgical procedure? Probably not.
But surely when you wake up and overcome post-anesthesia grogginess, it will be worth pondering this and the myriad other human actions that are contributing to potential climate calamity in the future.