>From Wikipedia: 'Geoengineering is the deliberate modification of Earth's environment on a large scale "to suit human needs and promote habitability".'
There are two main classes of geo-engineering: one dealing with radiation input to the Earth from the sun; the other dealing with radiation output, trapped by greenhouse gases. The former class is sometimes called Solar Radiation Management, SRM, and involves reflecting the sun's radiation back into space. The latter class generally involves techniques to lower the level of greenhouse gases in the atmosphere. It is worth noting that one of the almost certain consequences of global warming is the Arctic sea ice retreat, see: http://en.wikipedia.org/wiki/Arctic_shrinkage This could be a tipping point for the whole Earth climate system, as further warming of the Arctic could lead to massive methane release from permafrost - sufficient methane to cause runaway global warming. A common misapprehension is that greenhouse gas emissions reduction, if pursued vigorously enough, can prevent dangerous climate change. This might be true, if it were not for tipping points like the Arctic sea ice with its domino effect on methane release. The only way we may be able to prevent the disappearance of the Arctic sea ice is by cooling the Arctic region using SRM geoengineering. SRM geoengineering cannot be guaranteed to work, but nobody has any alternative approach. Emissions reduction cannot have an effect on the required timescale. The good news is that there are two different SRM techniques, either or both of which could be used to cool the Arctic: one using stratospheric aerosols and one which involves the brightening of marine clouds. If both are tried, with the greatest urgency, then we have a good chance to halt the decline of the Arctic sea ice. Any delay reduces our chances considerably, since the sea ice could disappear at end of summer 2013, or even earlier according to some experts. Cheers, John ----- Original Message ----- From: "Sam Carana" <[email protected]> To: "geoengineering" <[email protected]>; "geo-engineering" <[email protected]>; "greenhouse effect" <[email protected]> Sent: Wednesday, January 21, 2009 1:37 AM Subject: [geo] What is geo-engineering? > > What is geo-engineering? > > I was confronted with this question when reading two webpages: > 1. a recent NASA recent news release; and > 2. a submission to the Royal Society. > > > 1. The NASA news release includes the following paragraph: > > "The authors discredit the notion of "geo-engineering" solutions, > noting that with present cost estimates the price of artificially > removing 50 ppm of CO2 from the air would be about $20 trillion. They > suggest instead that improved agricultural and forestry practices > offer a more natural way to draw down CO2, noting that reforestation > of degraded land and improved agricultural practices that retain soil > carbon could draw down atmospheric CO2 by as much as 50 ppm. > Additional significant CO2 reduction could be achieved by using > carbon-negative biofuels to replace liquid fossil fuels and phasing > out emissions from natural gas-fired power plants, according to the > authors. They find that a combination of these approaches could bring > CO2 back to 350 ppm well before the end of the century." > > Source: Target Atmospheric CO2: Where Should Humanity Aim? > http://www.giss.nasa.gov/research/news/20081208/ > > > 2. An organization called biofuelwatch argues in a submission to the > Royal Society that: > > "geo-engineering should not be pursued as a policy option", because of > the "impact which those proposals would have on biodiversity". The > submission focuses on "Bioenergy with Carbon Capture and Storage > (BECS) and biochar". > > Source: Submission to Royal Society study on Climate Geo-engineering > http://www.biofuelwatch.org.uk/docs/RS_Geoengineering_Biofuelwatch.pdf > > > While we can have many comments on each of the above, shouldn't we > first clarifty what is geo-engineering? What appears to be called > geo-engineering by one organization, is referred to by NASA as natural > (as opposed to geo-engineering). > > What is your view? What is geo-engineering? > > > Cheers! > Sam Carana > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~----------~----~----~----~------~----~------~--~---
