Best Sources For Proving Global Warming Is Happening

I'd look for something that comments on the average global temperature remaining constAnt over the past 10 years and even dropping a 1/2 a degree this past year. That'll show an acceleration. Espcially with the massive amount of CO2 tha China has been putting out.

 

Try RealClimate.

 

Ditto. Absolutely the best source of information. Written by climate scientists, read by climate scientists and the general public. Almost the only site on this topic where the posted comments are worth reading. Go to the "Start Here" link or the Index link first. The "Responses to Common Contrarian Arguments" in the Index section is a good place to start.

For example, per the comment above, you might want to read "Antarctica is Cold? Yeah, we knew that", for a balanced discussion of antarctic temperature.

RealClimate

Key quote:

"Bottom line: A cold Antarctica and Southern Ocean do not contradict our models of global warming. For a long time the models have predicted just that."

Again, per the comment above, whether short-run temperature fluctuations must mirror the stead increase in CO2 (the "Chinese" reference above), you could read the RealClimate source material here:

RealClimate

Despite all the blather written about this, and the complexity of modeling climate, the basic story is pretty straightforward. It boils down to this:

1) Increased C02 will warm the earth significantly in the long run. To believe that the earth will not warm as a result of C02 increase, you would have to repeal a lot of basic physical laws.
2) The current C02 increase is definitely manmade.
3) The C02 we put into the air now will be there, changing climate, for a long, long time to come.
4) Other things may also affect climate now. Other things have affected climate in the past. That doesn't change points 1 to 3 a bit.
5) Nobody says that the increase will be quick, uniform over time, or uniform across geographic areas. To the contrary, climate scientists say the exact opposite. The fact that it isn't a rapid, linear, uniform temperature increase doesn't change points 1 to 3 a bit, and doesn't contradict the predictions of climate models.
6) There is legitimate uncertainty around many of the important details. That doesn't change points 1 to 3 a bit.

As a benchmark, as far as I can tell, the most commonly accepted estimate of the long-run impact of C02 increase is that a doubling of C02 from current levels would, in the long run, raise the average surface temperature by about 3 degrees centigrade. That increase would, in all likelihood, do a lot of damage (make the earth less livable for humans), although there is a lot of uncertainty there. At present, we've increased atmospheric carbon by about one-third over the pre-industrial-revolution baseline, and we're increasing it by just over one-half-percent per year.

I don't think anyone but the real fringe disbelieves point 1. Points 4, 5, and don't really require explanation as such, they're just a convenient way to categorize most of the denialist arguments. I'll briefly present the most straighforward evidence for points 2 and 3: it's our carbon, and our grandchildren are going to have to live with the consequences of it. On net, the main problem with getting people to understand the issue is that its happening very slowly and will persist a very long time.

Once you understand the time involved, you only need to ask a few key questions: How much is C02 increasing, how do we know the increase is man-made, and how long-lived is the increase in C02.

You can find the answers on RealClimate and elsewhere, but here they are in round numbers.

Using clean ice cores from the antarctic to measure historical C02 levels, it's pretty clear that the amount of C02 in the atmosphere was stable for at least 2K years prior to the start of the industrial revolution. You can express that as the amount of carbon in the atmosphere. It was about 600 gigatons. Currently, it's about 800 gigatons, with all the gain coming since the start of the industrial revolution, and with the rate of growth increasing over time.

So, we're about 1/3 over the baseline (equilibrium) amount, right now.

How do we know it's our carbon, and not some natural source. The simplest answer is, we've got receipts. Based on statistics of trade, we know how much fossil fuel gets burned each year, how much cement gets made (you drive C02 out of certain minerals to make cement), and we have a good estimate of the C02 release from land use changes (e.g., net deforestation).

After that, it's just arithmetic. We know how much carbon is in the atmosphere at the start of the year, we know how much we emitted during the year, we know how much carbon is there at the end of the year. And the net annual increase in atmospheric carbon is less than what we emitted. So, mother nature remains a net carbon sink (absorbing our carbon). The increase in C02 cannot be from natural sources, as a simple matter of arithmetic. If Nature were a net source of atmospheric carbon, then atmospheric C02 would have to be increasing faster than it currently does.

Roughly speaking, at present (I'm not going to look up the numbers but these are close), we emit 10 gigatons, Mother Nature absorbs 5 gigatons (out of the entire current excess of 200 gigatons above the pre-industrial-revolution baseline), and total carbon in the atmosphere goes up by 5 gigatons a year (or a bit over half a percent a year).

Recap: If C02 rises, we'll get significant warming. Nobody but the fringe denies that. C02 is now one-third higher than at the start of the industrial revolution. And, as a simple matter of arithmetic, we know that the increase is manmade. (There are other tests that validate that the increase is manmade, but the statistics of trade are sufficient).

So, the only other question is, how long does the excess C02 stay around? I mean, if it would go away in a few years, then if worst comes to worst, we all park our cars for a few years and the planet would heal itself.

No such luck. Look at the data above: of the current excess of 200 gigatons (above the pre-industrial-revolution baseline), Nature absorbs about 5 per year currently. The best estimates are that the carbon we emit today will still be significantly influencing climate for a couple of centuries into the future.

And that's what makes this such an ugly issue. By the time the damage is obvious even to the slowest learners among us, it'll be be much too late to do anything about it. So, the same models that predict the change also say that we'll need to act before we see the worst of the impact.

Now, as with all things in this area, there are people who will tell you that C02 only lasts 5 years in the atmosphere. Those people are confused. A free C02 molecule has a half-life of about 5 years from release to initial re-absorbtion out of the air (by dissolving in sea water, or becoming part of a leaf). That's true enough. But those absorbed C02 molecules are mostly immediately re-released into the air (dissolve out of the ocean, released as the leaf decomposes). So they've confused the half-life of an atmospheric C02 molecule (from release to initial re-absorption) with the half-life of an excess of C02 above the equilibrium level.

In fact, excess C02 in the atmosphere takes a very long time to be re-absorbed by the biosphere. The simplest empirical evidence showing that excess atmospheric carbon is long-lived is the "bomb carbon". Prior the the ban on above-ground nuclear explosions that went into effect in 1963(?), the civilized nations of the world got busy testing as many nuclear weapons as they could. In the atmosphere. Nuclear explosions generate C14, and that flurry of above-ground tests produced a big spike in atmospheric C14, basically doubling the level in a couple of years. Although that is not a perfect analog for the current increase in atmospheric carbon, it's close enough to show that the re-absorption of the excess is slow. Even now, atmospheric C14 levels are maybe 15 percent above the background (pre-1963) level. You can see a graph of that here:

Radiocarbon dating - Wikipedia, the free encyclopedia

In terms of understanding the basics, that's it. Higher C02 levels will warm the earth (or some basic physical laws are wrong, take your pick.) C02 levels are rising (or there's a vast conspiracy to fake the data, take your pick.) The increased C02 is manmade (or there's a vast conspiracy to fake fossil fuel use data, or the laws of arithmetic are wrong, take your pick.) The result will be a slow, uneven, warming of the earth's surface, measurable over a timescale of decades. The fact that it is slow and uneven, or that that the earth's temperature has changed over geological timescales in the past, or that other factors influence climate -- none of those negate the fundmental argument.

In terms of evidence that the change is real, the only advice I have to offer is that you have to talk to somebody who is smart enough to get the big picture. Most of the denialists are fundamentally cherry-pickers. They'll put one selected piece of data in front of you, and ignore the larger picture. So, if you say that 99% of the monitored glaciers in the world are in retreat, all at the same time, you'll have somebody blather about this here or that there glacier having retreated in the past. You talk about the average global temperature over this decade, you'll hear about the cold winter in China this year. You'll hear about the record-breaking extent of Northern Hemisphere snow cover (ie, square miles with some snow cover) this winter, but you'll never hear that it was so thin and melted so fast this spring that the spring snow cover was well below the recent average. And so on and so forth.

Other sources well worth reading are the NASA GISS and of course NOAA. Both have pages on climate change and provide excellent, readable summaries. For NASA GISS, start with their surface temperature page and work from there:

Data @ NASA GISS: GISS Surface Temperature Analysis (GISTEMP)

Well I do that but clearly I'm kind of a geek in this area.

NOAA is always worth stopping by:

NOAA - National Oceanic and Atmospheric Administration

For example, today there's an article showing that March land temperatures worldwide set a new record high. That's one tiny bit of data, but things like that are good to know when somebody shoves some cherry-picked cold temperature data your way. More importantly, they note in passing that the current La Nina (cold western pacific waters) weakened, which could be the initial indication that global temperatures are getting set to increase again.

 

I like this web site:

Main Page - Global Warming Art

It has data from many peer-reviewed sources in graph and linkable form with references. You only need two graphs really:

 

Why bother? These are people who have been trained to repeat what they hear over and over from the right wing media, which has become the mainstream. They've been trained so well that the response is now automatic. They can't think for themselves. They don't even realize that Bush himself even admits that GW is real. You're wasting your time if you expect them to think objectively. The collapse is happening, now. The evidence is everywhere and we can't stop it anyway. They'll realize it soon enough.

 

Alric, thanks, that's an excellent site.