Hi Eugene, I am posting your comment to the groups, because it's important, and because my direct response to you bounced!
You are absolutely right as regards needing a geoengineering fix. But your argument only applies to halting global warming, which we can do over decades, not to halting ice retreat. My argument is about short term - months. We need to start fixing the mess now - even if possible in time to measure effects of trials in Arctic this summer. The mess is catching up with us mighty fast. Who is going to listen to us? Stephen Salter has talked about being prepared for the panic when the sea ice reports come out for 2008. But people should have been panicking in 2007, with the record sea ice retreat. Does nobody realise what a dire situation we are in? Cheers, John ----- Original Message ----- From: Eugene I. Gordon To: [email protected] Cc: [email protected] Sent: Wednesday, January 21, 2009 12:55 PM Subject: RE: [geo] Re: What is geo-engineering? This is a useful input but it ducks the issue of greenhouse gas lifetime in the atmosphere; which I believe can be demonstrated for CO2 to be over 1000 years. Accordingly greenhouse gas emission reductions or elimination can only prevent the situation from getting worse; it cannot reduce the global average surface temperature everything else being the same, for over 1000 years. Moreover, when sunspots return we may have a very serious problem. Hence, geoengineering is obligatory as responsible inhabitants of this planet. We must fix the mess we created. ----- Original Message ----- From: John Nissen To: [email protected] ; geoengineering ; greenhouse effect Cc: Davies, John ; [email protected] ; [email protected] Sent: Wednesday, January 21, 2009 12:00 PM Subject: Re: [geo] What is geo-engineering? 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? [snip] --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
