8. what seems to have happened already as a result of global warming 9. what could happen in future?

Question

8. what seems to have happened already as a result of global warming 9. what could happen in future?

Answer 1

Since we're only one degree or so into the current warming, learly it's important to learn from paleontoloigcal examples of warming of several degrees to see what we're in for with regards to future consequences that are coming.

Sea Level Rise -

8. "Global averaged sea level continued to rise through 2006 and 2007. Modern satellite measurements reveal that since 1993, sea-level has been rising at an average rate of about 3 mm per year, substantially faster than the average for the 20th century of about 1.7 mm per year, estimated from coastal sea-level measurements. These coastal measurements indicate that the 2006/2007 global averaged sea level is about 200 mm higher than in 1870 and that since 1870 there has been a significant increase in the rate of the sea-level rise."

http://wcrp.wmo.int/documents/WCRPnews_2...

Rohling and his colleagues found an average sea level rise of 1.6m (64in) each century during the interglacial period.

Back then, Greenland was 3C to 5C (5.4F to 9F) warmer than now - which is similar to the warming period expected in the next 50 to 100 years, Dr Rohling said.

Current models of ice sheet activity do not predict rates of change this large. However, they also do not include many of the dynamic processes already being observed by glaciologists, the researchers said.

"The average rise of 1.6m per century that we find is roughly twice as high as the maximum estimates in the IPCC Fourth Assessment Report, and so offers the first potential constraint on the dynamic ice sheet component that was not included in the headline IPCC values," explained Dr Rohling.

http://news.bbc.co.uk/2/hi/science/natur...

9. "Instead of sea levels rising by about 40 centimetres, as the IPCC predicts in one of its computer forecasts, the true rise might be as great as several metres by 2100. That is why, they say, planet Earth today is in 'imminent peril.'"

http://www.heatisonline.org/contentserve...

"A one-meter sea level rise would wreak particular havoc on the Gulf Coast and eastern seaboard of the United States.

'No one will be free from this,' said Overpeck, whose maps show that every U.S. East Coast city from Boston to Miami would be swamped."

http://news.nationalgeographic.com/news/...

"If Earth's climate continues to warm, then the volume of present-day ice sheets will decrease. Melting of the current Greenland ice sheet would result in a sea-level rise of about 6.5 meters; melting of the West Antarctic ice sheet would result in a sea-level rise of about 8 meters (table 1). The West Antarctic ice sheet is especially vulnerable, because much of it is grounded below sea level. Small changes in global sea level or a rise in ocean temperatures could cause a breakup of the two buttressing ice shelves (Ronne/Filchner and Ross). The resulting surge of the West Antarctic ice sheet would lead to a rapid rise in global sea level.

Reduction of the West Antarctic and Greenland ice sheets similar to past reductions would cause sea level to rise 10 or more meters. A sea-level rise of 10 meters would flood about 25 percent of the U.S. population, with the major impact being mostly on the people and infrastructures in the Gulf and East Coast States"

http://pubs.usgs.gov/fs/fs2-00/

Ice sheet melt:

8. http://www.alertnet.org/thenews/newsdesk...

New research confirms that ice sheets in West Antarctica are thinning at a far faster rate than in past millennia.

http://www.barentsobserver.com/hottest-a...

"This winter might become the mildest winter in Northern Norway ever registered. So far the average temperature in parts of the region has been up to eight degrees Celsius above the normal."

"Ground-based surface temperature data shows that the rate of warming in the Arctic from 1981 to 2001 is eight times larger than the rate of Arctic warming over the last 100 years. There have also been some remarkable seasonal changes. Arctic spring, summer, and autumn have each warmed, lengthening the seasons when sea ice melts from 10 to 17 days per decade."

http://www.nasa.gov/centers/goddard/eart...

9. "This week, after reviewing his own new data, NASA climate scientist Jay Zwally said: "At this rate, the Arctic Ocean could be nearly ice-free at the end of summer by 2012, much faster than previous predictions."

Ominous Arctic Melt Worries Experts

'Arctic Is Screaming,' Say Scientists Seeing New Data; Worry Over 'Tipping Point'

http://abcnews.go.com/Technology/wireSto...

Extinctions:

8. "Prior major warmings in Earth’s history, the most recent occurring 55 million years ago . . . resulted in the extinction of half or more of the species then on the planet."

http://www.columbia.edu/~jeh1/2008/State...

It was the Earth's most severe extinction event, with up to 96 percent of all marine species and 70 percent of terrestrial vertebrate species becoming extinct. Because approximately 25 percent of species survived the event, the recovery of life on earth took significantly longer than after other extinction events. This event has been described as the "mother of all mass extinctions".

http://en.wikipedia.org/wiki/Permian-Tri...

9. http://www.killerinourmidst.com/methane%...

A careful examination of a large number of species in numerous parts of the planet projects that a stunning portion of them will be "committed to extinction" in just 50 years, with only modest global warming (Thomas, 2004).

Crop damage and rising food prices:

8. Food news: http://www.climatechangenews.org/nFood.h...

Hunger. Strikes. Riots. The food crisis bites

http://www.guardian.co.uk/environment/20...

"Across the world a crisis is unfolding at alarming speed. Climate change, China's increasing consumption and the dash for biofuels are causing food shortages and rocketing prices - sparking riots in cities from the Caribbean to the Far East. Robin McKie and Heather Stewart report on the millions facing starvation - and the growing threat to global security"

Hungry mob attacks Haiti palace

http://news.bbc.co.uk/2/hi/americas/7337...

9. http://www.commondreams.org/headlines04/...

"Already, according to Randall and Schwartz, the planet is carrying a higher population than it can sustain. By 2020 'catastrophic' shortages of water and energy supply will become increasingly harder to overcome, plunging the planet into war. They warn that 8,200 years ago climatic conditions brought widespread crop failure, famine, disease and mass migration of populations that could soon be repeated."

Answer 2

I'm going to refer you to my answer on this question for 8.  I think the answer to 9. may still be up to us.  I hope so anyway.