Global warming 'irreversible' for next 1000 years: study  

The ABC has a report on a gloomy assessment of global warming from the NOAA - Global warming 'irreversible' for next 1000 years: study.

Climate change is "largely irreversible" for the next 1,000 years even if carbon dioxide (CO2) emissions could be abruptly halted, according to a new study led by the US National Oceanic and Atmospheric Administration (NOAA).

The study's authors said there was "no going back" after the report showed that changes in surface temperature, rainfall and sea level are "largely irreversible for more than 1,000 years after CO2 emissions are completely stopped."

NOAA senior scientist Susan Solomon said the study, published in this week's Proceedings of the National Academy of Sciences journal, showed that current human choices on carbon dioxide emissions are set to "irreversibly change the planet."

Researchers examined the consequences of CO2 building up beyond present-day concentrations of 385 parts per million, and then completely stopping emissions after the peak. Before the industrial age CO2 in Earth's atmosphere amounted to only 280 parts per million.

The study found that CO2 levels are irreversibly impacting climate change, which will contribute to global sea level rise and rainfall changes in certain regions. The authors emphasised that increases in CO2 that occur from 2000 to 2100 are set to "lock in" a sea level rise over the next 1,000 years.

Rising sea levels would cause "irreversible commitments to future changes in the geography of the Earth, since many coastal and island features would ultimately become submerged," the study said.

Decreases in rainfall that last for centuries can be expected to have a range of impacts, said the authors. Regional impacts include - but are not limited to - decreased human water supplies, increased fire frequency, ecosystem change and expanded deserts.

Joe Romm at Grist says maybe we should do some geoengineering research just incase, even if its not the right way to solve the problem - Collecting Dust.

Heck, I say, let's do some geo-engineering research, but let's not be deluded into thinking that pursuing research is the same thing as having any reason to believe that research will lead to anything practical or affordable -- or any more successful than the billions we have flushed down the toilet trying to build a practical and affordable hydrogen car.

If geo-engineering CO2 out of the air is plausible and affordable at a large scale, it is only after serious mitigation, to go from, say, a brief peak at 450 ppm, back to 400 ppm or lower. Going from 1,000 ppm down to below 400 ppm is not only a staggering task to imagine -- where the heck would you put the hundreds of billions of tons of carbon? -- but it would also be too late to save the ocean from becoming one large, acidic dead zone, and, in any case, we probably would have crossed carbon cycle tipping points that unleash the methane in the peatlands and permafrost.

Bottom line: A few decades of prevention is worth 1,000 years of cure misery.

Grist also has a post on another report advocating geoengineering - Sci-Fi Dreamin'?. Playing with fire if you ask me...

Massive, futuristic schemes to spur land and sea into sucking up greenhouse gases may help the fight against global warming but are no substitute for reducing the pollution itself, scientists said Wednesday.

Once dismissed as daft or dangerous, some of these "geoengineering" projects can be of use in fending off the juggernaut of climate change, but only if they go hand-in-hand with cuts in carbon emissions, they warned.

"Geoengineering" describes large-scale schemes such as erecting sunshades or mirrors in space, sowing the stratosphere with white particles or whitewashing building roofs to reflect sunlight, or scattering iron filings in the ocean to promote carbon-gobbling algae. None of these projects has been launched on any significant scale.

Green groups are deeply suspicious of them, saying the most ambitious ventures could wreck ecosystems, carry an astronomical price and postpone tough decisions on reducing emissions of fossil-fuel gases that cause the problem.

But promoters of geoengineering are now getting a closer hearing as political efforts to resolve climate change remain bogged down. They argue that geoengineering, by slightly cooling the planet, would buy time for humans to get their carbon pollution under control.

In a paper published on Wednesday in the journal Atmospheric Chemistry and Physics Discussions, researchers at Britain's University of East Anglia make the first attempt at calculating the effectiveness of these schemes. They do not analyze environmental impact, nor do they estimate the cost.

"We found that some geoengineering options could usefully complement mitigation [of emissions], and together they could cool the climate," said Tim Lenton, a professor of environmental sciences. "But geoengineering alone cannot solve the problem."

The report said:

-- To gain a quick cool by 2050, building a deflector in orbit and sowing the stratosphere with fine sulfur particles are the best bet. But they also carry "a heavy burden of risk." The particles have to be replenished, and the sunshade would need maintenance. Any breakdown would cause temperatures to rise at a stroke.

-- "Fertilizing" the ocean to boost plankton growth has chiefly long-term potential, as it would take centuries or millennia to really get up to speed.

-- Over the shorter term, it makes more sense to plant trees to soak up atmospheric carbon dioxide, and to use energy by burning biomass by pyrolysis so that its residues are returned to the soil as charcoal, a form of carbon that remains stable for centuries or millennia.

-- Painting roofs and roads white and other actions to help land surfaces reflect solar rays is of limited and local value. It could cool cities a little, but globally would be of little effect.

-- The benefits of some geoengineering schemes have been in exaggerated in the past, and calculations about their effectiveness are fraught with errors.

The study comes amid an intensifying debate among climate experts about geoengineering. In its landmark report in 2007, the UN's Intergovernmental Panel on Climate Change (IPCC) blasted geoengineering options as "largely speculative and unproven, and with the risk of unknown side-effects."

In the most controversial experiment to date, scientists aboard a German research vessel, the Polarstern, are in the Southern Ocean where they plan to carry out what they describe as a small-scale test in iron fertilization.

Germany's environment ministry has spoken out against the experiment, but the research ministry has stood by it.