Most parts of the world save Africa had a particular week when the first Homo sapiens walked in from some other place and looked around for the first time. It took several generations to find camping ground near moving water and to figure out what you can put in your mouth and what animals want to put you in theirs, but eventually humans adapted to each new land.
New lands adapted to us in return. The first few thousand years after human colonization were catastrophic for species that couldn’t adapt to the two-legged social toolmakers. The dawn of humanity coincided with a major extinction spasm. Eventually, the species that survived reached a detente with humanity that survived more or less until today.
One reason why humans reached a relative peace with the remaining species is that for most of our history we could only modify the world’s environment to a certain degree. The kind of profound changes that could wipe out species more adaptable than Smilodon or Megatherium only joined the human toolkit during the last two centuries.
On a positive note, some of the earliest, obvious side-effects have already come and gone. Cities once blackened by soot – London or my hometown Pittsburgh – now sport clean air and rivers that are if not drinkable, then at least (on a good day) swimmable. Whales have bounced back. American pesticide use became safer and more sensible since Rachel Carson wrote her book.
The issues that we managed so far share two important characteristics. First, negative effects stood up and announced themselves. It’s hard to ignore when a river catches fire or half of your kids have respiratory disease from the coal soot.
Second, a solution needs to be relatively obvious and practical. It isn’t that hard to make a pulping plant stop dumping mercury into the sea or fence off an area to logging when stripping it would cause floods and encourage fires.
By contrast, if people profiting from death can credibly sow doubt then you can bet they will sow for all they’re worth. Unfortunately, the CO2 greenhouse effect is just that kind of issue. For nearly half a century after scientists first recognized the potential risk of supercharging the atmosphere with carbon dioxide, evidence remained intangible enough for Philip Morris-style doubtmongering to pay off handsomely. At the same time practical solutions to greenhouse warming are notably impractical.
That semi-invisible phase of greenhouse warming is now over. Gardeners and naturalists notice plants blooming months earlier, altitude-limited species moving higher and latitude-restricted species showing up farther north. Glacier ice is in retreat nearly everywhere on Earth save for the deep-frozen interiors of Antarctica and Greenland. Farmers are having a hell of a time predicting what the local climate will do to their crops from year to year.
Take three news bits that I noticed in the past week.
* Arctic sea ice may reach its lowest level in history this summer.
A number of predictions have been issued in the past several months, all indicating that 2008 has at least a decent chance of beating out 2007 for the title of the greatest summer sea ice loss on record.
In fact, some experts have concluded that the North Pole itself may be covered by water, rather than ice, during the peak of the annual melt season at the end of the summer, and that the Northwest Passage could be ice-free for a time as well.
* Massive arctic ice shelves aren’t doing very well.
Dramatic evidence of the break-up of the Arctic ice-cap has emerged from research during an expedition by the Canadian military.
Scientists travelling with the troops found major new fractures during an assessment of the state of giant ice shelves in Canada’s far north.
[…] One of the expedition’s scientists, Derek Mueller of Trent University, Ontario, told me: “I was astonished to see these new cracks.
“It means the ice shelf is disintegrating, the pieces are pinned together like a jigsaw but could float away,” Dr Mueller explained.
According to another scientist on the expedition, Dr Luke Copland of the University of Ottawa, the new cracks fit into a pattern of change in the Arctic.
“We’re seeing very dramatic changes; from the retreat of the glaciers, to the melting of the sea ice.
“We had 23% less (sea ice) last year than we’ve ever had, and what’s happening to the ice shelves is part of that picture.”
These two stories together underline why the arctic sea is a particular problem for dealing with greenhouse warming. The key word is albedo.
The “greenhouse effect” is a normal part of the world’s thermostat. On average the Earth reflects about 30% of incoming sunlight. Snow reflects up to 80%, land reflects 10-40%. Importantly, open water reflects less than 10%, meaning that almost all of the light energy that reaches open water stays to warm it. If CO2 and other molecules in the atmosphere didn’t transform light energy into heat, because energy mostly bounces off our planet, most of the Earth would be about as warm as the antarctic ice cap.
There are two ways of tinkering with the global heat balance that are pertinent to our discussion. First, if you increase the light-absorbing gas in the air then less light energy will escape into space. That’s the greenhouse effect.
The second way of tinkering with the thermostat is to change the surface of the Earth so that it absorbs more light energy. By far the most effective way of doing that is to transform snow-covered sea ice with its tiny albedo into open water. This has nothing to do with greenhouse warming per se, but the effects add up. Open water created by CO2-mediated sea ice melting will add that much more warming to the global system, causing what edumificated types call positive feedback.
* Finally, local spots of acidified ocean have started showing up much sooner than expected.
Climate models predicted it wouldn’t happen until the end of the century.
So Seattle researchers were stunned to discover that vast swaths of acidified sea water are already showing up along the Pacific Coast as carbon dioxide from power plants, cars and factories mixes into the ocean.
In surveys from Vancouver Island to the tip of Baja California, the scientists found the first evidence that large amounts of corrosive water are reaching the continental shelf — the shallow sea margin where most marine creatures live. In some places, including Northern California, the acidified water was as little as four miles from shore.
“What we found … was truly astonishing,” said oceanographer Richard Feely, of the National Oceanic and Atmospheric Administration’s Pacific Marine Environmental Laboratory in Seattle. “This means ocean acidification may be seriously impacting marine life on the continental shelf right now.”
This is pretty weird, but that has more to do with timing than effect. We already know that cramming the atmosphere with CO2 will acidify the ocean. That is because the dissolved form of CO2 is H2CO3, carbonic acid. More CO2 in the atmosphere means more carbonic acid in the surface ocean. Eventually, when the ocean equilibrates entirely with the atmosphere the ocean should drop by 0.5 pH points, a significant enough drop to threaten hundreds of species (including coral) that depend on basic ocean water to stabilize their calcium carbonate shells.
Ocean acidification will eventually disrupt the hell out of marine ecosystems. In fact it was measured in the Pacific years ago, but nobody expected that Iraqis would resist foreign occupation acid waters would move inland this fast. Combine this with the anoxic ‘dead zones’ that have become increasingly common and I wouldn’t go long on the Pacific salmon fishery.