Posted by Larry Hoover on February 5, 2009, at 9:17:10
In reply to Re: Global Warming or Cooling? You asked :-), posted by seldomseen on February 4, 2009, at 18:51:43
> However, one does have to look at evidence and draw independent conclusions when forced to do so. In my opinion there is a preponderance of evidence that the climate *is* changing. I also think that the apparent speed with which it is occuring strongly suggests that humans, while perhaps not outright causing this change, are exacerbating the situation.
I'm definitely going to have to agree with you.
IMHO, most critics of global warming depend upon criticisms of the land temperature records collected over the last hundred years or so, and statistics derived therefrom. But there's a lot more evidence than that.
1. The Greenland ice sheet is melting at rates that, in some places, now are more than 100 times the rates recorded just 40 years ago.
2. Ice shelfs that have been attached to Antarctica for 100's of thousands of years are breaking away and melting. If I recall correctly, there is one that is half the size of France just holding on by a thread. It's possible it will break away this year.
3. Ethnohistorians trying to collect as much traditional knowledge and language from elderly Inuit in Arctic Canada before they die have discovered that these elders are seeing birds for which they have no names. The northern range of what we know as sparrows are now encroaching on territories where the oral history does not have a record of their existence.
4. The spring blooming times of native plants have been recorded by natural historians over centuries. Over the course of the 20th century, some spring bloom times advanced by as much as 19 days, with the average at about 10 days. None, so far as I know, have receded.
5. Breeding success of some migrant birds has declined dramatically. Those that migrate based on food availability tend to be doing all right (excluding concerns over habitat destruction), whereas those which migrate based on signals based on day length are not. Arrival times on breeding grounds had evolved such that nesting and subsequent hatching would exactly correspond with peak food supply, especially of insects. Peak insect activity has often passed before the birds are ready to feed their newly hatched young, and breeding success has declined dramatically.
6. Summer ice pack in the Arctic is receding so quickly that it is possible that the entire Arctic will be ice free in summer, within years. Multi-year ice (ice that doesn't melt entirely away in summer, which accumulates greater depth in subsequent winters) is in the most dramatic decline.
7. Permafrost, which by its very name suggests that it is enduring, is melting at an alarming rate. Buildings with foundations in what was thought to be permanently frozen soil are now sinking into mud. The same goes for some stretches of pipelines. They are actually building huge refrigerators to refreeze the melting permafrost under critical installations.
8. Glaciers are receding all around the world at rates that even the most excessive estimates of only a decade ago did not predict. It is possible that rivers in India (the Ganges is included, I think) will dry up seasonally because their sources high in the Himalayas will have melted away. There is no record of that ever happening in the thousands of years of historical records covering that region.
There is more, but I don't need to go on and on. I'm an empiricist, in that observations are the only true science that we have. These observations, we know. How we interpret them is not science, although it is what scientists are wont to do. I believe the preponderance of the evidence is that global warming is well underway. What it will mean to us will be revealed when we are able to observe the effects over time.
Lar
poster:Larry Hoover
thread:877985
URL: http://www.dr-bob.org/babble/social/20090116/msgs/878195.html