Climate Change - How do we know humans cause it?

Climate is a constant balancing act. 2% sounds insignificant, but a little can go a long, long way when it tips the balance. Another balance will be reached, we aren’t going to destroy the planet. But it may be a balance that we don’t find nearly as comfortable.

So those who talk of “only 2%” don’t understand the problem.

Yeah, because humans are completely incapable of doing anything to the environment, like hunting animals to extinction or anything :rolleyes:

The geographic record clearly shows climatic shifts over extended periods of time without any human intervention. And we do know that humans have been dumping greenhouse gases into the atmosphere since the industrial age. But aside from that, saying anything with the certainty appreciated by the public is extremely difficult because the environment is so fricking huge! Even the best meteorological and climatology models is lacking.

But the evidence so far indicates that it doesn’t take much to tip the scales out of homeostasis. Yeah, things will probably shift back in decades or centuries, but we don’t really know. And in the interim, life gets annoying, because it doesn’t take much of a shift in average temperature to turn a February snowfall into an icestorm that wipes out your electrical grid.

The idea of the urban heat trap may be a fact, but what you are saying here (i.e. that it explains all the observed temperature rise) is a hypothesis. It needs to be backed up by refereed journal articles. If you have no more cites, I’m forced to conclude that it’s just a fringe theory not accepted by the mainstream scientists.

Then why does your cite say the two results can be reconciled by a more accurate climate model? Show me an article which says ground-based and space observations are contradictory, and that the space observations are considered more accurate.

This is a very serious accusation. Do you have any evidence that any of the scientists are lying? I hope you’re not just using it as an excuse to throw away the papers you don’t agree with.

The way the general media deal with this question really pisses me off.

There seems to be no public debate at all about global warming/climate change, in the meeja it is taken as a given. No room for doubt at all. So while the sensible debate is asking what possible changes would mean by 2100 people with no scientific basis at all blame today’s weather (well yesterday’s/last weeks) on “climate change”. The phrase “global warming” is less popular now I think because it’s harder to blame snow and rain on “warming”. Hot summer == global warming, wet winter == climate change, wet summer?

Back in the seventies the scare was that we were heading for a new Ice-age :slight_smile:

Yes I think it would be a good thing not to be adding crap like CFCs into the atmosphere but the way forward is not to blame every rained-out barbecue on friggin climate change.

As to the OP, we don’t know. Do like qts says and read the Lomborg book.

In essence, you determine the cause of the changes by correlating them to human behavior. The big problem, as you can see by the various posts, is that correlation does not prove causation. While we can correlate certain climatic changes with changes in human behavior, it is much harder to prove that those climatic changes were caused by (and only by) those human behaviors. Clearly, the inferences grow stronger as the correlations become more direct and varied. Bottom line - we simply don’t know for sure the extent to which humans have affected the climate.

And, on the one hand, you have the folks who say, “Well, let’s not wait until we know for 100% sure. This could be a HUGE problem. Let’s at least go on what we think might be true. It would be stupid not to.” And you have the folks who say, “Look, if you don’t know it’s a problem for sure, and you don’t know what’s causing it for sure, it’s stupid to try to solve it.”

I feel very strongly both ways.

A good refutation of your claims: The Fossil Fools – George Monbiot

True, but when you consider that theories (models) predict such a causal relationship, and that no other cause adequately explains the observed climate changes, the evidence starts to become overwhelming.

I’m not saying that climate change doesn’t exist or that we shouldn’t be doing more about pollution. Nor am I about to side with a bunch of lassez-faire right wingers.

My irritation is caused by the day-to-day assumption that yesterday’s unusual weather was caused by climate change (rather than that butterfly).

Also the way the wrong targets are picked on, people will bring climate change into a discussion about widening the M25 or the building of a new bypass. The real problem isn’t SUVs and more roads, it is heavy industry, air transport and frickin China. What is the point of even discussing UK emissions when the Chinese are running their industry on coal?

“but when you consider that theories (models) predict such a causal relationship, and that** no other cause adequately explains the observed climate changes,** the evidence starts to become overwhelming.”
Just so. But the problem with that line of reasoning, of course, is that just because we don’t know of any other compelling explanation, that doesn’t mean that there isn’t one. Minor fluctuations in the temperature of the earth over time may not even follow an identifiable pattern, for instance. I don’t mean to suggest that our understanding of natural laws is incomplete, although it most certainly is to some degree, but that what we don’t understand about the universe, the solar system, and our planet may be quite significant. Even to the extent that it may be that there are, in fact, causes for the changes in the climate that we do not appreciate as yet. For instance, maybe the planet’s core temperature changes by a degree or so and that temperature difference migrates (unevenly) to the surface in, say, 1000 or so years. Maybe that’s a cause of El Ninos. Maybe that’s a part of the climate change equation. Just sayin’

Because the UK can’t directly influence Chinese emissions any more than it can influence the number one greenhouse gas producer, the USA. All it can do is try to support international protocols and get its own house in order.

It is true that we may never prove beyond reasonable doubt that global warming is caused by human activity.

IPCC data - it’s all there. Ignore it if you wish.

Yes, it might be a coincidence that temperatures have risen in the 20th Century in correlation with releasing so much CO[sub]2[/sub] which was previously stored deep under the Earth, such that we are undeniably anthropogenically forcing it far off equilibrium.

Yes, we understand the Earth’s climate pretty much not at all - we have no idea what caused violent climate changes in Earth’s relatively recent past.

The question is, given such violent unpredictable fluctuations in the past: Do we really want to conduct a vast unsupervised experiment on what we can get away with?

Well, global warming or not, there is something happening.

For instance, in the 1930’s a study was taken in Monterey Bay’s waters to catalogue the species living there at the time. This study was done at the Hopkins Marine Station (Part of Stanford University) where a 95 square yard section was marked and the species living within it catalogued. The bay has also had 80 years worth of temperature readings taken.

In 1993 the lab decided to do the same study in the same area (the markers left behind were still there). They discovered that the habitat profile changed from a more Northern California profile to that of a Southern California Profile.

Temperature wise: “The data showed that, during the 60-year interval between the two animal surveys, annual mean water temperatures increased on average by about 1.3 F [0.7 C],” says Somero.

More significantly, he adds, peak summer temperatures in August rose nearly 4 F (2.2 C).

More here: Global warming: lessons taught by snails and crabs : 11/00

Global warming or not? I can’t say, but at least locally here, the waters have warmed up.

Perhaps that means we’ll actually be able to swim in the bay without wetsuits soon? :slight_smile: