This is the first installment of a four-part series to be published each Wednesday on Action Needed to Stop Global Warming.
1. How Warm is Too Warm?
2. Worldwide Emissions Target
3. U.S. Emissions Target
4. Technologies to Get Us There
According to the Intergovernmental Panel on Climate Change (see IPCC report [PDF] and description of the IPCC), global warming is “unequivocal”, and almost certainly due to human activities. Moreover, the IPCC says, global warming is already doing significant damage – more droughts, wildfires, heat waves, and downpours, and more intense hurricanes. What can we do about it?
We begin by considering how much warmer it can get before climate change becomes dangerous and irreversible. Unfortunately, our influence over this is limited by two factors:
- We can’t reverse the warming we have already caused. Per the IPCC report, CO2 concentrations since the 1800’s have increased from 280 parts per million (ppm) to 380 ppm, causing global temperatures to increase by about 1.3oF. To undo that warming, we would have to return the CO2 concentration to its pre-industrial level. This would require removing 800,000 million metric tons of CO2 from the atmosphere, and we just don’t have the ability to do that. To put that amount in perspective, consider that Richard Branson’s Virgin Earth Challenge will give $25 million to anyone who can remove just 0.1% of that amount.
- It’s going to get warmer than it is today. Even if we stabilized greenhouse gas concentrations today – a virtual impossibility – the rate of warming would slow, but not stop for another 30 years. This delayed warming, caused by (among other factors) how long it takes for the ocean to heat and cool, is called “warming in the pipeline”. The IPCC estimates that warming in the pipeline will increase global temperatures by an additional 1.0oF, no matter what action we take. But we can – and better – stop it there.
Scientists have identified tipping points in the climate system for different parts of the world, beyond which major climate disruption with dangerous and irreversible impacts will occur (see our Visible Impacts report [PDF]). The most immediate of these tipping points is in Greenland, which has begun to lose its ice sheet. The ice is currently two miles thick, extends over an area equivalent to Mexico, and contains 10 percent of the earth’s fresh water.
Satellite measurements show that the Greenland ice sheet recently began losing mass and the rate of loss appears to be accelerating. Scientists estimate that if global temperatures rise 3.6oF above pre-industrial levels (2.3 oF above what they are now), the melting will become unstoppable. Within 100 years or so, the Greenland ice sheet could be gone, causing a 20 foot increase in sea levels. This is not a legacy we want to leave to future generations. Imagine a world without the Everglades or Wall Street.
Since the consequences of losing the Greenland ice sheet are global and dire, the line in the sand [PDF] that scientists have drawn is the tipping point for Greenland. Global average temperatures must not rise more than 3.6oF above pre-industrial temperatures, 2.3oF above current temperatures, or just 1.3oF above what the temperature will be after the warming in the pipeline takes place.
The next post in this series will discuss the emissions limits needed to keep us from crossing the 3.6oF tipping point.
5 Comments
Thanks for the specifc info. Do you know of anyone creating middle or high school curriculum for teaching sustainable living? We desperately need it.
CDavey: I agree that educational material is badly needed – see my post on my experience teaching teachers from Tennessee:
http://blogs.edf.org/climate411/2007/03/01/webcast_to_teachers/
Here are some educational resources you might find useful:
– On Science: http://www.koshlandsciencemuseum.org/exhibitgcc/index.jsp
– On Carbon calculator/personal steps: http://www.fightglobalwarming.com
– On technologies: http://www.princeton.edu/~cmi/resources/stabwedge.htm
You people have absoleutely no idea what you are talking about. Glaciers are growing and shrinking all across the globe and it isn’t a constant theme, as in all are shrinking or all or growing. For example, Antartica you know that big ice sheet? It is the coldest it has been in the last 50 years. The hottest years in America were in the 1920’s and the 1930’s not now, does anyone remember the dust bowls in the midwest? Basically go to google.com and type in global warming + scam and then tell me if you want to argue ok?
Polar ice is shrinking at an unprecedented rate, and faster than scientists predicted:
http://blogs.edf.org/climate411/2007/09/14/grim-outlook-for-polar-bears/
“Basically go to google.com and type in global warming + scam and then tell me if you want to argue ok?”
And if you type in “AIDS + scam” you will ‘discover’ that HIV doesn’t cause AIDS, even though we know that it does.
And if you type in “9/11 + scam” you will ‘discover’ that the building came down not because of airplanes but because of explosives, even though the explosives couldn’t create the effect we all saw.
And if you type in “P&G (or nay other large company, religion, or ethnic group) + scam” you will ‘discover’ that these people are running the world behind the scenes, even though they can’t ALL be running the world.
And if you think about any of the arguments above, and apply some logic, and test the hypotheses, and the references you will really discover for yourself that they are all bogus.
If you want to find a conspiracy theory then you will find one. But that doesn’t mean it’s the best explanation of the facts. Particularly when it doesn’t actually explain the facts.
Quentin
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[…] Part 1 of 4: How Warm is Too Warm? […]
[…] 1. How Warm is Too Warm? 2. Worldwide Emissions Target 3. U.S. Emissions Target 4. Technologies to Get Us There In Part 1 of this series, I defined the global tipping point as the melting of the Greenland ice sheet, which could cause sea levels to rise 20 feet. In Part 2, I showed by how much global emissions of carbon dioxide (CO2) must drop to avoid this tipping point. They must start to decline around 2020, drop 50 percent by 2050, and drop at least 75 percent by the end of the century. […]
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[…] The Year 2000 line shows what happens if greenhouse gas concentrations stay at current levels. Temperatures will continue to rise slightly because it takes some time for carbon emissions to translate into global warming. Scientists call this the "warming in the pipeline". […]
[…] As Bill explained in his post "How Warm is Too Warm?", many experts consider one tipping point to be a warming sufficient to melt the Greenland ice sheet. Over time, this would cause sea levels to rise over 20 feet, flooding heavily populated coastal areas around the world. […]
[…] The implication of this ocean-induced lag time is that we have less time to act than it first appears. The tipping point for losing the Greenland ice sheet may be just 2.3 degrees Fahrenheit above today. If you factor in the warming in the pipeline, about half of that amount is already gone. […]
[…] The House must move quickly in January to ensure that national climate legislation is passed this year. The longer we wait, the deeper emissions cuts will have to be, increasing costs, and increasing the risk of passing the tipping point after which catastrophic climate change becomes inevitable. […]
[…] The Bali Roadmap gives developing countries an unprecedented opportunity to dramatically ramp up efforts to reduce deforestation. This will significantly help efforts to achieve the greenhouse gas emissions reductions that are vital to keeping global warming below 2°C, which scientists generally agree is the tipping point for climate change. […]
[…] Needed to Stop Global Warming 1. How Warm is Too Warm? 2. Worldwide Emissions Target 3. U.S. Emissions Target 4. Technologies to Get Us […]
[…] a system. For example, when temperature reaches 32°F, ice changes into water. There also are "tipping points" in global warming. The best known is the Greenland Ice Sheet, which could begin a slow, […]
[…] of global temperature often center around "tipping points" – the points after which qualitative climate change become inevitable. The most commonly […]
[…] down to where they need to be by 2020. This would greatly increase costs, and risk our passing the tipping point. var object = SHARETHIS.addEntry({ title:’share’, summary:’Share’}, {button:false}); […]
[…] Even if we stabilized greenhouse gas concentrations today, the rate of warming would slow, but not stop for another 30 years. This delayed warming, caused by (among other factors) how long it takes for the ocean to heat and cool, is called “warming in the pipeline”. The IPCC estimates that warming in the pipeline will increase global temperatures by an additional 1.0oF [0.6oC], no matter what action we take. But we can – and better – stop it there. Environmental Defense Fund, Climate 411, How Warm is Too Warm? Part 1, 7 March 2007 http://blogs.edf.org/climate411/2007/03/07/tipping_point/ […]