?

Log in

No account? Create an account
Climate Change I: sources of evidence for change - MoonScape [entries|archive|friends|userinfo]
e_moon60

[ website | My Website ]
[ userinfo | livejournal userinfo ]
[ archive | journal archive ]

Climate Change I: sources of evidence for change [Oct. 28th, 2009|08:24 am]
e_moon60
[Tags|, ]
[Current Mood |awake]

Although this is not a rant, it's also not an invitation for every anti-climate-change enthusiast in the known universe to come barging in here and argue.  You have your spaces to hold forth, which I don't go causing trouble in, and I have mine.

Having issued that warning, I was privy to another discussion in a closed list, and once more amazed at the misunderstanding of the original thesis and subsequent events within the scientific community as well as in the public mind.

The evidence for global warming did not come (never came) from climate models alone.  So rebuttals to global climate change based on the flaws of models misses the point.  The evidence comes from multiple sources.

1. The geological record of past climate and its relationship to various atmospheric conditions.  This research really began in the 1950s, when serious work with ice cores and pollen analysis, tree-ring data, and radiocarbon dating (less accurate but with a longer range) gave the first substantive links between physical and biological evidence of paleoclimates.  The International Geophysical Year (1957) gave a big push to such research, but some had begun before then.  In other words, through the 1950s, '60s, and '70s, and continuing to the present, increased data, increased refinement of research methods, and direct advancements in research methods, allowed scientists to correlate climate to atmospheric gas composition.

2. Geophysical evidence in the present day includes the rapid melting of glaciers and ice sheets and rising sea levels, rising global sea temperatures and global mean temperature, etc.; geochemical evidence includes higher carbon dioxide content of the air and increasing acidification of sea and fresh water.  

3. Meteorological evidence includes poleward shifting of dates of first frost, increased variability in seasonal temperatures and rainfall, increased variability in seasonal fluctuations of high-altitude winds (jet streams), etc.

4. Biological evidence includes the poleward migration of cold-intolerant plant species, poleward migration of cold-intolerant vertebrate and invertebrate species both in the oceans and on land, increasing desertification of semi-desert regions, winter survival of pest species formerly killed off by hard freezes.   In the Arctic, melting of permafrost has already begun on the flanks of melting glaciers, with release of additional greenhouse gases from the decay of long-frozen plant materials, only some of which carbon dioxide is used by the new plant cover.   A mismatch between migratory species and their food sources due to changes in temperature and rainfall that affect both plants and insects has been demonstrated in Europe and North America.

Contemporary changes are readily observable and have increased in the past 30 years.   Some of them I have personally observed: semi-tropical plants migrating two "planting zones" north, changes in migration patterns and the mismatch of food source to migrant,  milder winters in the past 10 years v. the previous 30, changes in rainfall patterns with a shift of jet streams to the north, etc.

To argue that these changes--predicted by the original hypothesis--are not caused by global warming would require an alternative explanation.  So far, no anti-climate-change enthusiast has offered such an explanation.

LinkReply

Comments:
[User Picture]From: hugh_mannity
2009-10-28 02:51 pm (UTC)
I've always thought that climate change was a constant. Back in the '70s it was all "ZOMG!!! ICE AGEEEE!!! WE'RE ALL GONNA FREEZE" and now it's the opposite. I wish the experts would make up their minds.

Either way. The climate will change sooner or later. It always does.

What I don't agree with is the current focus on human activity as the de facto cause. The climate was going through significant changes long before there were enough of us to have any effect whatsoever and will continue to do so long after we are dust. That doesn't give us carte blanche to carry on laying waste to the planet any way we like, we have a duty and responsibility to our children not to trash the family mansion.



(Reply) (Thread)
[User Picture]From: jonquil
2009-10-28 03:04 pm (UTC)
"I wish the experts would make up their minds."

That's not, actually, the way science works. One set of experts -- and it was only a subset -- said "I think this is what is going on." A later set of experts said "Your theory is disproven by this evidence, here's what is going on." Science is not static; if it were, it wouldn't be science.

What is wrong, badly, is reporting of science. Reporters aren't trained to evaluate whether what "a scientist" says is well-supported -- what is the scientist's publication record, and how many people cite his/her work? If it's human research, how many people were in the study, and for how long? Have you interviewed other experts in the field? -- and thus reporting switches from fad to fad without ever doing the sort of research that would be expected for, for instance, crime reportng.

What I don't agree with is the current focus on human activity as the de facto cause.

The problem is that the degree of change, and the curve of change, correlates precisely with the Industrial Revolution and the increasing use by industrialized civilizations of carbon-based fuels. This isn't like any fluctuation scientists have seen in recorded history; it's a sharp upward trend, and the curve matches precisely the curve of increased carbon use. To argue that the change is not related to humans increasing the CO2 in the atmosphere (and it has demonstrably increased, as shown by ice samples, among other things), you need to provide an alternate explanation of how all that CO2 got there.
(Reply) (Parent) (Thread)
[User Picture]From: caitlin
2009-10-28 03:11 pm (UTC)
What I don't agree with is the current focus on human activity as the de facto cause. The climate was going through significant changes long before there were enough of us to have any effect whatsoever and will continue to do so long after we are dust. That doesn't give us carte blanche to carry on laying waste to the planet any way we like, we have a duty and responsibility to our children not to trash the family mansion.

My first reaction (before I finished reading the above paragraph) was: "What, so you think we should just sit back and do nothing?

Upon finishing the paragraph, however, I realize that we do agree that making a mess of the planet = not a good thing.

I have always thought that pollution reduction ought to be tried anyway (with a possible concentration on the so-called greenhouse gases) because how much worse off will we be if we as a species clean stuff up on the planet and find out that, oh, ok, climate change ISN'T our fault, but OOH, look! We have a clean planet now!
(Reply) (Parent) (Thread)
[User Picture]From: e_moon60
2009-10-28 03:55 pm (UTC)
Back in the very early '70s, the first papers on the potential of rising CO2 to cause global warming came out. So it was not ALL "we're gonna freeze" in the 1970s. There have always been people worried about a new ice age--those doing so in the '70s figured we were due one because of the time since the last one.

Yes, climate changes. There's normal variation within large variation. For the past 10,000 years we've had a climate that was predictable enough (despite things like the "Little Ice Age" in the 1600s) to allow human civilizations to rise and develop.

Your reasoning that because the climate changed when we weren't around, we cannot be responsible for any of the current warming is flawed. A large human population wielding heretofore impossible powers is another factor--not the only factor--and as with my rowboat analogy, one more thing driving climate change can make climate change go farther faster.
(Reply) (Parent) (Thread)
[User Picture]From: green_knight
2009-10-28 04:32 pm (UTC)
The climate will change sooner or later. It always does.

Yes and now. A lot of past changes can be related to volcanic eruptions, which means that you get a lot of particles including solids and CO2 in the atmosphere at once. We can't stop those, but... sound somewhat familiar?

It's not very difficult to work out the negative consequences of the way humans treat the planet. Maybe cleaning up our act will not have a very big effect on the overall system (this geographer thinks differently), but here's the point: we have everything to lose if we ignore things, and nothing to lose if we take it seriously and take action.

'Global Warming' _is_ a slight misnomer. What we're getting is more extreme weather events, more often. Hundred year floods three times in a decade, that sort of thing. And we, as a species, are *not* flexible enough to deal with that, at least not well.
(Reply) (Parent) (Thread)
[User Picture]From: masgramondou
2009-10-29 03:12 am (UTC)
It's not very difficult to work out the negative consequences of the way humans treat the planet. Maybe cleaning up our act will not have a very big effect on the overall system (this geographer thinks differently), but here's the point: we have everything to lose if we ignore things, and nothing to lose if we take it seriously and take action.

Apart from a likely collapse of the global economy that is. Look if you examine the energy requirements of current human civilization you discover that in order to meaningfully reduce CO2 emissions etc. you need to lose something like 20%* of planetary GDP. This is not a good thing althouh some environmentalists seem to actually think this would be a good thing because they think the resultant economic collapse would lead to a massive die-off of humanity. Almost certainly they are wrong and a GDP collapse would result in further environmental degradation and more people are forced (back) into subsistence agriculture. Said agriculture
a) is rarely sustainable or efficient
b) leads to larger families
c) and hence leads down a vicious cycle of more population degrading even more of the environment

'Global Warming' _is_ a slight misnomer. What we're getting is more extreme weather events, more often. Hundred year floods three times in a decade, that sort of thing. And we, as a species, are *not* flexible enough to deal with that, at least not well.

I'm not sure about flood frequencies per se but as a general statement that includes hurricanes and other wind events that claim is not sustained by the facts.

I do know that floods are becoming more destructive in part because of humanity's distressing habit of building even more stuff on flood plains. A good deal of the drought issue (not all I concede but much) is caused by water (mis)use and having large populations in near desert conditions. California being the poster child for this. Elimintaing greater LA and the farming in the central valley would almost certainly make all the current water fights go away.

It should be noted that a large chunk of the increased frequencies of hurricanes, tornadoes etc. seems to be increased reporting rather than anything else. If you look at work by Roger Pielke Jr and/or Ryan Maue it is clear that wind events are not increasing over recorded time. An example (not from either) is this paper on tornados:
Diffenbaugh, N.S., Trapp, R.J. and Brooks, H. 2008. Does global warming influence tornado activity? EOS, Transactions, American Geophysical Union 89: 553-554.

*number taken from memory - it is order of msgnitude correct
(Reply) (Parent) (Thread)
[User Picture]From: green_knight
2009-10-29 09:01 am (UTC)
Energy requirements are a) not written in stone, and b) can be met by less polluting sources than currently practiced, so you're argueing a strawman. We already have the technology to produce electrical appliances, cars, and machinery that have a reduced energy requirement without making any difference to the user.

Innovation is not bad for the economy. Innovation drives economies. Currently, a lot of money goes into the hands of a few oil and gas producers. Wouldn't you rather meet your energy needs by something that was produced locally and created jobs locally?

As for the 'subsistence agriculture' picture you paint, there are a number of things wrong with it. Not in the least that people who can no longer support themselves in industrial or service sector jobs tend to move to places they think will support them better. Also, information technology is spreading: people all over the world realise that there are ways of improving their yields that work. Last but not least, population growth or not is a complex subject, and certainly not tied to a requirement to use different energy sources in the developed world.

as a general statement that includes hurricanes and other wind events that claim is not sustained by the facts.

Short version: hurricanes are created over spots of ocean that are very warm. If you warm up the whole planet, you get more hot spots, for longer, and in locations you didn't before. You should also look into El Nino/La Nina events, neither of which are, for the most part, particularly beneficial to the United States, both of which are becoming more frequent.
(Reply) (Parent) (Thread)
[User Picture]From: e_moon60
2009-10-29 05:35 pm (UTC)
Collapse of the global economy could be caused by many things, including global warming with its associate sealevel rise, increased shortage of fresh water, etc. In fact, as global warming continues, its negative economic effects will stress the global economy. The global economy is not in a steady state, and has not been in one since it became global rather than local/regional.

As mentioned before, just stopping tropical deforestation would do more to reduce CO2 emissions than turning off the power plants (would not, however, reduce other harmful effects of said power plants.)

Droughts are atmospheric phenomena--changes in rainfall distribution, frequency, and intensity are not directly related to overpopulating dry areas. Desertification in the face of normal rainfall is the result of human activity--including overpopulating dry parts of the planet--but you're ignoring the reasons for that...some of them so far insoluble with current political and economic strategies. In Africa, for instance, increasing population and inability to go somewhere else with better soil has led to intense pressure on agriculture production--very short-sighted management that has degraded an already poor soil badly, placed impossible demands on water supplies, etc. Deforestation to open new crop land results in rapid soil degradation and changes in local climate as the soil heats (heating increases the amount of water vapor the air can hold, and thus, in the same conditions, lessens rainfall.) More people mean more soil compaction, which also reduces soil productivity and the ability of soil to absorb rain and let it reach groundwater.

But trying control population growth is a hotter-button issue than global warming. So is changing practices...if you're reading in the agricultural-research end of things, you're aware that there are signs of serious trouble ahead in the management of crop diseases and pests in the most productive and necessary food crops--what produces spectacular yields in Iowa can and does turn up its toes and die in the Sudan.

Combine the worldwide changes in rainfall patterns and amounts with the increased world population (your focus on California is too narrow) and you have trouble--trouble that will certainly affect the global economy. When you talk of "eliminating greater LA and farming in the central valley" as a cure for "the current water fights" you are not being any more practical than those you disagree with. Where are you going to put those 14 million people? What about the work they do that is not just self-sustaining (the garbage collectors, telephone linemen, store clerks) but exported? What land will replace in productivity the central valley and its irrigated fields?

But don't answer that. I have work to do and need to get back offline.

(Reply) (Parent) (Thread)
[User Picture]From: jonquil
2009-10-28 03:00 pm (UTC)
I wish you luck. The only arguments I've seen are "Scientist X says it isn't global warming!" and "Scientists [n.b. SOME scientists] in the 1970s said there was global cooling and they were wrong, so clearly global warming is wrong too!"
(Reply) (Thread)
[User Picture]From: e_moon60
2009-10-28 04:01 pm (UTC)
If those are the only arguments you've seen, that's because you aren't reading the literature itself. It does not take a science degree to read good science journals (it helps, and I now have one, but I was reading NATURE and SCIENCE, two top fast-publishing journals, for years before I got back to college and got my second degree.) There's nothing to stop any citizen who's reasonably literate from going to the source and spending the time to figure out what's being said by whom on what grounds. Though in fact there have been reasonably good articles and presentations outside the scientific literature.

Moreover, the fact that A was wrong when he predicted global cooling does not mean (could not mean) that B was wrong when he predicted global warming. Anyone who tells you that is using false logic. (I wish to goodness we taught formal logic in the schools...it would prevent a lot of misunderstandings.)

(Reply) (Parent) (Thread)
[User Picture]From: jonquil
2009-10-28 04:23 pm (UTC)
I'm sorry, I didn't make my position clear.

I am completely on board with the science of global warming. I was citing arguments I've heard, and which I find in no way convincing.

[Edit: And my husband and I have been saying "Logic 101 should be required for high school graduation" for years -- but then we're both geeks.]

Edited at 2009-10-28 04:24 pm (UTC)
(Reply) (Parent) (Thread)
[User Picture]From: rwglaub
2009-10-28 10:12 pm (UTC)
My position is the same as Bjorn Lonborg's. Climate change is here, it's real, but it's so far along that we can't change it, and that we should be putting all of our efforts into alleviating it's effects, especially in the Third World.

My big beef is with the politicians on both sides of the issue who are trying to use it to push their own agendas. My biggest concern are with the ultra-leftists in the European Union, the ex-Marxists, who are using this as an excuse to bring back the centralized command economies that didn't work before. Plus the politicians who want to monitor everything and fine citizens huge amounts for unknowingly violating one of their rules (see Britain).
(Reply) (Thread)
[User Picture]From: green_knight
2009-10-28 11:37 pm (UTC)
If we don't put efforts into doing something, we make it worse. The biggest thing you can do in order to alleviate the effects is to *stop making it worse*.
(Reply) (Parent) (Thread)
[User Picture]From: bagfish
2009-10-29 05:43 pm (UTC)
... the ex-Marxists, who are using this as an excuse to bring back the centralized command economies that didn't work before. Plus the politicians who want to monitor everything and fine citizens huge amounts for unknowingly violating one of their rules (see Britain).

Examples please? I think your statement here is complete and utter rubbish. My reason for thinking this? I'm British and live in the UK and the picture you paint of "people being fined huge amounts for violating rules" in this sentence is not one that is remotely recognisable.

Also *LOL* at ex-Marxists in the EU - I don't think so, the majority of EU governments are centerist or rightward leaning (Merkel, Sarkozy and Berlusconi as ex-Marxists is a laughable idea). Where are these putative command economies of which you speak?
(Reply) (Parent) (Thread)