At least I give you credit for recognizing that global warming is happening. That puts you a step up from the dolts in this country that think its not, despite the overwhelming scientific evidence and visual proof that is.
Here is the science behind man's contribution to global warming:
"The skeptic argument...
"There is no actual evidence that carbon dioxide emissions are causing global warming. Note that computer models are just concatenations of calculations you could do on a hand-held calculator, so they are theoretical and cannot be part of any evidence." (David Evans)
Statement doesn't say glob
What the science says...
Direct observations find that CO2 is rising sharply due to human activity. Satellite and surface measurements find less energy is escaping to space at CO2 absorption wavelengths. Ocean and surface temperature measurements find the planet continues to accumulate heat. This gives a line of empirical evidence that human CO2 emissions are causing global warming.
Uh, no. The last line is incorrect. The last line presumes that coincidence implies causation.
The historical reality is that CO2 concentrations go up AFTER the warming cycle starts.
The reality is that the CO2 concentrations in the current warming cycle began to rise hundreds of years after the cycle's commencement. Just like in the past. That humans have added more CO2 is undeniable.
The case that this additional gas caused the warming is false.
The case that the warming is being driven by the excess CO2 is unproven.
The case for the Runaway Greenhouse is absurd.
And unproven.
The line of empirical evidence that humans are causing global warming is as follows:
We're raising CO2 levels
Yep.
Human carbon dioxide emissions are calculated from international energy statistics, tabulating coal, brown coal, peat, and crude oil production by nation and year, going back to 1751. CO2 emissions have increased dramatically over the last century, climbing to the rate of 29 billion tonnes of CO2 per year in 2006 (EIA).
Fair enough.
Atmospheric CO2 levels are measured at hundreds of monitoring stations across the globe. Independent measurements are also conducted by airplanes and satellites. For periods before 1958, CO2 levels are determined from air bubbles trapped in polar ice cores. In pre-industrial times over the last 10,000 years, CO2 was relatively stable at around 275 to 285 parts per million. Over the last 250 years, atmospheric CO2 levels have increased by about 100 parts per million. Currently, the amount of CO2 in the atmosphere is increasing by around 15 gigatonnes every year."
Yeah, that's the third time you've said humans have raised CO2 levels. I think we all agree on that part.
Now. You say the CO2 concentration was "relatively stable" for the last 10,000 years.
So, during the Mid-Holocene Altithermal and the Medieval Warm period, the CO2 levels were "relatively stable". That means there are significant causes of warming not related to CO2 levels, so significant they can raise global temperatures significantly above current levels with out causing lasting harm to the environment.
What are those sources of warming and are they active today?
The question is: How much.
According to radiative physics and decades of laboratory measurements, increased CO2 in the atmosphere is expected to absorb more infrared radiation as it escapes back out to space. In 1970, NASA launched the IRIS satellite measuring infrared spectra. In 1996, the Japanese Space Agency launched the IMG satellite which recorded similar observations. Both sets of data were compared to discern any changes in outgoing radiation over the 26 year period (Harries 2001). What they found was a drop in outgoing radiation at the wavelength bands that greenhouse gases such as CO2 and methane (CH4) absorb energy. The change in outgoing radiation was consistent with theoretical expectations. Thus the paper found "direct experimental evidence for a significant increase in the Earth's greenhouse effect". This result has been confirmed by subsequent papers using data from later satellites (Griggs 2004, Chen 2007).
You are aware that no one denies that CO2 is a greenhouse gas, right? And that we know what the phrase "greenhouse gas" means, right?
Naturally one expects that increased CO2 in the atmosphere will show stronger absorbtion bands. Duh.
That does not mean CO2 is CAUSING global warming. After all, CO2 is merely a small percentage of the total greenhouse gas in the atmosphere. Think WATER VAPOR. Water vapor is a thousand times as prevalent as CO2, and it's concentration shifts daily. How's the IR absorption bands from H2O coming along? Any significant changes? How's the emission spectra for the earth's surface doing? And impressive declines there?
When greenhouse gases absorb infrared radiation, the energy heats the atmosphere which in turn re-radiates infrared radiation in all directions. Some makes its way back to the earth's surface. Hence we expect to find more infrared radiation heading downwards. Surface measurements from 1973 to 2008 find an increasing trend of infrared radiation returning to earth (Wang 2009). A regional study over the central Alps found that downward infrared radiation is increasing due to the enhanced greenhouse effect (Philipona 2004). Taking this a step further, an analysis of high resolution spectral data allowed scientists to quantitatively attribute the increase in downward radiation to each of several greenhouse gases (Evans 2006). The results lead the authors to conclude that "this experimental data should effectively end the argument by skeptics that no experimental evidence exists for the connection between greenhouse gas increases in the atmosphere and global warming."
Again, you have to show that this warming can be attributed 100% to CO2, and not to other factors. Cloud cover is amazingly effective at keeping the planet warm...but clouds are made of water, not CO2. So, yeah, I can dispute his conclusions because he's not providing a big enough picture. Also, no one says that greenhouse gases don't keep the planet warm. They do. The discussion is to what extent does human activity contribute.
Got any evidence sorting the natural from the unnatural contributions? Don't forget, you have to include the cause of the current warming cycle, and you don't even know what that is.
From 1970 to 2003, the planet has been accumulating heat at a rate of 190,260 GigaWatts with the vast majority of the energy going into the oceans. Considering a typical nuclear power plant has an output of 1 GigaWatt, imagine 190,000 nuclear power plants pouring their energy output directly into our oceans. What about after 2003? A map of of ocean heat from 2003 to 2008 was constructed from ocean heat measurements down to 2000 metres deep (von Schuckmann 2009). Globally, the oceans have continued to accumulate heat to the end of 2008 at a rate of 0.77 ± 0.11 Wm−2, consistent with other determinations of the planet's energy imbalance (Hansen 2005, Trenberth 2009). The planet continues to accumulate heat.
Amazing.
All the heat, and the planet's been cooling for almost a decade.
Are you people sure you want to turn the heaters off?
So we see a direct line of evidence that we're causing global warming.
No, that's not what you presented. You presented a set of unconnected facts and drew unsupported lines between them. I believe this is called "stringing them along".