Our Changing World
Subject: Global warming in terms of wildlife changes and ecosystem destruction assessed by the Millennium Assessment
I've recently returned from my annual holiday ski-touring in Canada . While there I could see the changes in the ice this year compared to earlier years. What three years ago was a dimple in the snow and last year had opened into a small hole that one had to ski around, this year was a large crevice one unquestionably had better avoid. Ice no longer covered the buttresses of rock which now jut out narrowing a favorite pitch we ski down to the flats of the lake. This was my sixth year skiing in the Selkirks of British Colombia and the changes in the ice pack are noticeable even to my eye accustomed to computer screens rather than subtle changes in nature.
I came back home knowing that the world was changing but not fathoming how just much. I came back to find the special April issue of National Wildlife http://www.nwf.org/national wildlife/index.cfm?issueID=74
devoted entirely to Global Warming. Rather than arguing the statistics comparing decades of comparative temperature data, the editors focused on what they know best; wildlife. Their approach for examining the effect of a warming environment was to catalog changes to wild life.
The changes caused by global warming are more noticeable the further north you go. This is probably why I can see the change in British Columbia but would be hard pressed to point out something clearly different here in Denver . Global warming is adversely affecting the Arctic at a rate “more rapidly and persistently than at any time since the beginning of civilization,” according to Robert Corell, chair of the Arctic Climate Impact Assessment. The permafrost is melting, changing the very structure of the land, collapsing beaches, riverbanks and draining wetlands. Eskimo whalers have to adapt to later freezing and earlier melting of the ice pack. Higher than normal spring melts have swept thousands of migrating caribou to their deaths as they attempted to follow traditional migration routes across rivers swollen with runoff that all historical records suggest should still be frozen. Insects emerge earlier, birds arrive earlier, the American Robin now migrates far into the arctic north, a bird for which the native inhabitants have no name in their language.
These same shifts in wildlife behavior are occurring all over the globe. Take the humble American opossum which hates cold weather. During the US Civil war, possum was a southern animal, familiar to Confederate stew pots but few other places: their range extended only as far north as Pennsylvania . Since then it has spread north into New England in deep into Canada . Possum is an adaptable animal, most aren't.
A recent study published in Nature suggested that as many as one third of all wildlife species could be headed for extinction in the next 50 years.
The twentieth century was the warmest of the past 1,000 years and 19 of the hottest years on record occurred after 1980. The rate of warming in the Arctic increased eight times faster during the past 20 years than the previous 100 years. Average winter temperatures in Alaska and Western Canada have risen as much as 7 degrees during the past 60 years. Antarctic temperatures have increased by about 4.5 degrees since the 1940's. Ice Shelves in Antarctica are collapsing at an alarming rate; ice shelves which have been built up over the last 12,000 years. In the US Rockies and the European Alps freezing level has shifted upward almost 500 feet since 1970. On Kilimanjaro 80% of the snow cap has melted. The 150 glaciers in Montana 's Glacier Park have reduced to 30. In Russia 's Ural Mountains the tree line has moved 500 feet higher during the last century. In Canada 's Banff Park tree level has shifted 180 feet upward since just 1990. In Washington , DC a survey of 100 flowering plants, revealed that 89 bloom an average of 4.5 days earlier than they did in 1970. In Edmonton , Alberta a similar survey showed that overall spring flowering occurs eight days earlier than in 1945. The growing season in Europe has increased by 11 days since 1960. Oak trees in England leaf two weeks earlier than they did in 1965.
I could go on with this list for quite awhile. This issue of National Wildlife certainly does. The publishers are just a bunch of tree huggers anyway. Some might argue that I'm just being sentimental; the world is always changing, species either adapt or go extinct. Who cares about butterflies and Eskimos?
Our news media were too caught up with current events in recent weeks to bother reporting on the Millennium Ecosystem Assessment (MA) which was published a few weeks ago. http://www.millenniumassessment.org/en/index.aspx
The MA is a mammoth $24 million multi-agency report that focuses on the importance of ecosystems, not for their own sake and all the cute animals in them, but their importance to people. It took 1300 scientists working in 95 countries over four years to put this report together. Basically it is a global inventory of natural resources. The research in the MA is all thoroughly peer reviewed, and amounts to the fullest assessment ever of the present state of ecosystems and of life on our planet.
The report's conclusion: we are living beyond our means.
According to the report approximately 60% of the planet's “ecosystem services”- natural products and processes such as water purification- are being degraded or used unsustainably. The most obvious changes cataloged are the conversion of natural systems to farmland and the felling of forests for lumber. Forests have been almost completely eradicated from 25 countries and in another 29 forest coverage has dropped by 90%. More virgin land has been cleared since 1945 than during the entire 18 th and 19 th centuries. Both fisheries and fresh water supplies are already in the danger zone in much of the world. Irrigation has doubled the use of surface water since 1960. Fertilization has doubled the available nitrogen and tripled the available phosphorous in our lakes and river since 1960. This has lead to eutrophication of these fresh water supplies, creating dead zones. The CO2 in the atmosphere has increased by about a third since the start of the industrial revolution with 60% of that increase occurring since 1959.
Extinction rates are about 1,000 times higher than the norm seen throughout evolutionary history. Maybe I'm just sentimental but I don't think this is good.
When I was in the sixth grade, my mother helped me do a science experiment that I have never forgotten. She brought me into the lab at the hospital and helped me inoculate an Erlenmeyer flask filled with growth media with a pinch of E. coli bacteria. Every half hour throughout the day we took a sample of the media and ran it through a cell counter to track the population change of my bacteria. Supplied with ample food and oxygen the number of bacteria in the jar increased exponentially hour after hour until they ran out of something, whether it was food or oxygen I don't recall, and in minutes all but a few of the bacteria died off. With mom's help I drew these results on a graph, a sudden spike of life in a test tube that died off far faster than it grew. I've never forgotten that image and reviewing information like this brings it back. We have a finite number of resources in this jar in which we live.
What is most striking about the Millennium Assessment is the lack of pessimism in it. ‘This is the situation,' it seems to say, ‘it isn't hopeless, it's simply time we did something about it.' Our politicians will need some encouragement to take on politically risky challenges such as those this report points out. They will need every bit of encouragement we can give them. Otherwise it is easier to look the other way.
A simplified summary of the Millennium Assessment Report can be found at: