Ice Cores and Global Warming

Six years ago I attended a lecture on ice core samples and what they reveal about the history of greenhouse gases in the Earth's atmosphere. Before I listened to this lecture, I entertained a lot of skepticism about the greenhouse effect. But the ice cores convinced me. At that time, the samples revealed the history of carbon dioxide and methane concentrations, going back maybe 1000 years. The data matched measurements from other techniques, and it was overwhelmingly convincing. Since that day, I have been a firm believer in the greenhouse effect, and I've tried to convince everyone I know that we can't afford to "wait and see" on such a big issue.

Today the New York Times reports the results of a new study on ice cores, taking the data back 650,000 years. The complete study is reported in Science. According to the NYT article:

"They've now pushed back two-thirds of a million years and found that nature did not get as far as humans have," said Richard B. Alley, a geosciences professor at Pennsylvania State University who is an expert on ice cores. "We're changing the world really hugely - way past where it's been for a long time."

James White, a geology professor at the University of Colorado, Boulder, not involved with the study, said that although the ice-age evidence showed that levels of carbon dioxide and the other greenhouse gases rose and fell in response to warming and cooling, the gases could clearly take the lead as well.

"CO2 and climate are like two people handcuffed to each other," he said. "Where one goes, the other must follow. Leadership may change, or they may march in step, but they are never far from each other. Our current CO2 levels appear to be far out of balance with climate when viewed through these results, reinforcing the idea that we have significant modern warming to go."

In the past two years, a huge volume of strong evidence has been amassed in support of the global warming theory. There is no room for dispute: the concentration of greenhouse gasses is higher than ever before, and it will cause the Earth to warm. The real questions are "how much," "how soon" and "how fast?"

Last week it was reported that the first global warming refugees have been evacuated from the disappearing Cartaret Islands in Papau New Guinea. According to Retuers (via Yahoo News):

For 20 years, the 2,000 islanders have fought a losing battle against the ocean, building sea walls and trying to plant mangroves. Each year, the waves surge in, destroying vegetable gardens, washing away homes and poisoning freshwater supplies.

Papua New Guinea's Carteret islanders are destined to become some of the world's first climate change refugees. Their islands are becoming uninhabitable, and may disappear below the waves.

A decision has been made to move the islanders to the larger nearby Bougainville island, four hours' boat ride to the southwest. Ten families at a time will be moved, over one to two years, once funds are allocated for the resettlement program.

...

A United Nations panel of more than 2,000 scientists has predicted that average sea levels are likely to rise between 9 and 88 cm (3.5 to 35 inches) by 2100, mainly because of a build-up of heat-trapping greenhouse gases in the atmosphere from the burning of fossil fuels, such as oil and coal.

Sea levels are expected to rise because of a melting of ice caps and because water expands when it warms. If the entire Greenland ice sheet melted in coming centuries, for instance, sea levels would rise by seven meters.

Many scientists say a 50 cm rise in sea levels could cause a 50 meter retreat of the coastline in low-lying areas.

At the higher end of the forecast, the sea would overflow the heavily populated coasts of countries such as Bangladesh, and cause low-lying island states like the Indian Ocean's Maldives and South Pacific's Kiribati and Tuvalu to disappear.

...

"It's a matter of survival for us. If our islands go under, we all go under," said President Anote Tong of Kiribati, 33 low-lying islands covering 5 million sq. km (1.9 million sq. mile) in the South Pacific and home to about 100,000 people.

"We move back from the shoreline, (but) how far can we move back? We are in danger of falling off the backside of our islands," Tong told Reuters at a recent Pacific leaders' summit in Port Moresby, capital of Papua New Guinea.

Kiribati's highest point is 87 meters (261 ft) above the sea. Most islands are coral atolls covered with just 2.5 meters (just over 8 ft) of hard sand and meager soil. There are no rivers and most islands enclose a lagoon.

Two uninhabited Kiribati islands, Tebua Tarawa and Abanuea, disappeared underwater in 1999, according to the South Pacific Regional Environment Program, and the island of Tepuka Savilivili no longer has any coconut trees due to salination.

...

A recent UN study forecast that some 50 million people could became environmental refugees by 2010, driven from their homes by desertification, rising sea levels, flooding and storms linked to climate change.

Tuvalu Prime Minister Maatia Toafa hates the term "environmental refugee" but admits his 11,600 people may have to abandon their South Pacific island homes.

Tuvalu consists of a fringe of nine atolls, with the highest point no more than 5 meters (17 ft) above sea level, but most a mere 2 meters (6.5 ft) high.

A small island off the capital Funafuti has already disappeared beneath the sea and some islanders have been forced to grow crops in tins because the soil has become too salty.

In February, only days before Kyoto came into effect, Tuvaluans in the capital watched high tides and strong winds send waves crashing across the main road. Children rode the waves on makeshift surfboards, trailing behind cars and vans dashing for higher ground.

"The prediction is (that) in 50 years Tuvalu will not exist," said Toafa. "Resettlement is impossible in the country because all the islands are low-lying," he said from Funafuti.

The rising sea level also threatens millions who live in low-lying coastal areas, such as Bangladesh and New Orleans (we've already seen a preview of what can happen in New Orleans).

In spite of the rising tsunami of evidence for global warming, there are still some obnoxious nay-sayers who have embraced the quixotic mission of debunking the entire scientific community. At JunkScience.com, Steve Milloy and Berry Hearn are busily posting links to damning Fox News articles. In response to the ice core study, the JunkScience authors say

These guys may well be right about atmospheric CO2 levels, after all, the Earth has been in an ice age for the last couple or three million years - we're very grateful for the current interglacial making the place much more life-friendly - however, just because atmospheric CO2 levels are currently recovering from their recent historic miniscule level does not a major driver of climate make.

This is a common mistake of pseudo-science: refute the evidence we have by appealing to the evidence we don't have, and assume that the missing evidence exists somewhere, just waiting for us to find it. This style of argument bolsters the claims of every quack, scam, cult and unscientific fad. The folks at JunkScience.com chose an appropriately descriptive title for themselves and the junk they write.

The scientific consensus on global warming is extremely well established. This is not agreement of some tight-knit insiders' group. "Consensus" represents the agreement of papers, theories and evidence spanning thousands of researchers in multiple disciplines, in multiple countries, spanning several decades. The current position is clearly documented by all the relevant US scientific associations and societies, as summarized in Science. The article also repeats the results of a survey of all peer-reviewed scientific papers on global warming:

The 928 papers were divided into six categories: explicit endorsement of the consensus position, evaluation of impacts, mitigation proposals, methods, paleoclimate analysis, and rejection of the consensus position. Of all the papers, 75% fell into the first three categories, either explicitly or implicitly accepting the consensus view; 25% dealt with methods or paleoclimate, taking no position on current anthropogenic climate change. Remarkably, none of the papers disagreed with the consensus position.

Admittedly, authors evaluating impacts, developing methods, or studying paleoclimatic change might believe that current climate change is natural. However, none of these papers argued that point.

Even the Intelligent Design folks managed to get one peer-reviewed paper. If there was any merit to the case against global warming, we should expect at least one lousy paper to make it somewhere. Surely all scientists can't be so committed to their biases as to prevent publication of every last challenge to their prevailing viewpoint.

Even as the naysayers are evaporating, ardent conservatives like the Evangelicals, and energy corporations like GE are becoming convinced. According to USA Today:

GE Chairman Jeffrey Immelt recently announced that his company, which reports $135 billion in annual revenue, will spend $1.5 billion a year to research conservation, pollution and the emission of greenhouse gases. Joining him for the announcement were executives from such mainline corporations as American Electric Power, Boeing and Cinergy.

Religious groups, such as the United States Catholic Conference of Bishops, National Association of Evangelicals and National Council of Churches, have joined with scientists to call for action on climate change under the National Religious Partnership for the Environment. "Global warming is a universal moral challenge," the partnership's statement says.

And high-profile politicians from both parties are getting into the act. For example, California Gov. Arnold Schwarzenegger has called for a reduction of more than 80% over the next five decades in his state's emission of greenhouse gases that heat in the atmosphere.

To be sure, many companies — most notably oil industry leader ExxonMobil — still express skepticism about the effects of global warming. And the Bush administration has supported research and voluntary initiatives but has pulled back from a multi-nation pact on environmental constraints.

The administration was on the defensive last week when The New York Times reported that a staff lawyer has been softening scientific assessments of global warming. White House spokesman Scott McClellan defended such action as a routine part of a multi-agency review process.

Nonetheless, the tides of change appear to be moving on.

"As big companies fall off the 'I don't believe in climate change' bandwagon, people will start to take this more seriously," says environmental scientist Don Kennedy, editor in chief of the journal Science. Companies aren't changing because of a sudden love for the environment, Kennedy says, but because they see change as an opportunity to protect their investments.

"On the business side, it just looks like climate change is not going away," says Kevin Leahy of Cinergy, a Cincinnati-based utility that reports $4.7 billion in annual revenue and provides electricity, mostly generated from coal, to 1.5 million customers. Most firms see global warming as a problem whose risks have to be managed, he says.

Power companies want to know what sort of carbon constraints they face — carbon dioxide is the chief greenhouse gas — so they can plan long term and avoid being hit with dramatic emission limits or penalties in the future, he says.

There are still a lot of questions about how global warming will play out. As consumers, we sit at the bottom of the political and economic food-chain. Individuall, we are low-level emitters. Our conservation efforts, boycotts, and so on will not accomplish much on the global scale. I believe the most useful thing an individual can do is to donate their desktop screen-saver time to the project at ClimatePrediction.net. By joining this project, you can become part of a massive networked supercomputer dedicated to understanding global warming. It only runs while you are away from your computer, so you don't lose anything by donating the idle cycles. With any luck, the results of the climateprediction.net study will reveal that we aren't all going to die after all.