There are a lot of things floating around in the "news media" about climate change. A lot of it is correct, some of it is foo-foo, and far too much of it is deliberate obfuscation by people who have an agenda. There is a crude expression for scientists who sell their souls to corporations, but this blog will not go there.
I thought it might help to provide a short word summary of what's going on:
1. Virtually all climate specialists not paid by Big Oil agree that the Greenhouse Effect is real. It was first reported in the scientific literature by Joseph Fourier (of Fourier transform fame) in 1824. It's been tested and proven repeatedly ever since.
2. There is a lot of yearly and decadal variability in climate data. Anyone can cherry-pick the weather data to prove any point they want to - but that's not science. If someone is trying to convince you that climate change is not happening, ask yourself: who's paying this guy?
3. CO2 in the Earth's atmosphere has gone from 315 ppm in 1958 to 400 ppm today (Mauna Loa observatory). Virtually all scientists with integrity accept that most if not all of this change is due to human activity.
4. The last time the atmospheric CO2 reached this level, according to the geologic record, was during the Pliocene. At that time, about half of Florida was underwater (including the places where ~80% of Florida's population now lives). I've pulled Pliocene marine fossils out of land deposits in Florida with my own hands; they are on my bookshelf.
5. There is a latency of CO2 after it gets into the atmosphere, and some scientists calculate this to be about 30 years. Translation: it tends to stay there. The oil you burn today will really be impacting you 30 years later.
6. A gallon of gasoline, which weighs 3 kg, will produce about 10 kg of CO2. The extra comes from the oxygen you might want to breathe instead. That's 50 kilometers in my car.
7. Nearly 5 billion people on Earth want to have a high-protein lifestyle like their grandparents could not have even dreamed of. This means vastly-increased herds of vegetation-eating, meat-producing animals. The amount of methane a cow produces is truly breath-taking (pun intended): up to 500 liters of methane a DAY. That's more than a 5-drawer file cabinet. Methane is 37 times more potent than CO2 as a Greenhouse Gas.
8. Increased temperatures mean more glacier calving, more melting or Arctic, Antarctic, and Greenland ice masses. Less white stuff on the ground means the darker - light-and-heat-absorbing - under-layers will be exposed, trapping more solar heat and making the inevitable change non-linear. Translation: the changes will likely accelerate with time.
It's not hard to draw conclusions from all this:
One is NOT to buy beachfront property. Anywhere.
Another is to move to the Pacific Northwest, or to the Canadian prairie provinces. They will be the winners.
There are several unresolved questions still:
1. How quickly will the global climate change consequences befall us? This depends on climate modeling, and these models are fraught with assumptions and disagreements. But they are beginning to coalesce.
2. Seawater rise, bigger and more devastating hurricanes and tornados, and greater and more terrible droughts and wildfires, are among the many likely consequences, but how <i>bad</i> can be can only be roughly modeled.
3. The effect of climate warming on gas hydrates (methane clathrates) that lie beneath most continental shelves is a HUGE unknown. Most estimates (from seismic reflection data) put the amount of these clathrates at many orders of magnitude greater than all other known hydrocarbon reserves combined. Gas hydrates are methane trapped in water ice below ~300 meters of seawater, the depth where the pressure and cold temperatures currently trap them. The hydrocarbon-poor Japanese are pouring huge resources into extraction technologies right now.
This last one leads to inevitable questions about non-linearity in climate forcing - and tipping-points. In other words, can things get out of control? Is it already too late - will we see a runaway temperature rise? Will we see inundation of most of the world's great cities (a Waterworld)?
The geologic record says yes, it's happened before for natural reasons - but the geologic record also shows that the Pliocene warm period came on far more slowly than what we are seeing in the modern climate: hundreds of thousands of years to raise CO2 levels, as fast as humanity has done in the past half century.
We are already in unknown territory, and precise predictions are probably not going to be correct.