“Over the most recent 25-65 years, every study put the human contribution at a minimum of 98%, and most put it at well above 100%, because natural factors have probably had a small net cooling effect over recent decades (Figures 3 and 4).
Read more at http://planetsave.com/2012/01/19/what-is-causing-global-warming/#tLOvIHiwzVZKmyS7.99 “

Willing to drown them as well?

1) Start bailing and try to figure out what you can jam in the hole?

2) Sit back and wonder if something else might turn up? You know, a submarine might surface
and loan you a pump or a big fish might cruise along and get stuck in the hole. Or something you’ve never heard of before, a truly world unique event might happen.

I’m thinking we should bail….”

If the leak was going to take 50 to 100 years to sink my boat, I don’t think I would work up too much of a sweat with the bailing bucket just yet. I imagine you would scream “We’re all going
to die!” and frantically claw at the few drops of water that were running down the side of the boat.

To each his own…

“Isn’t it possible that there are unknown or undiscovered forces that dwarf any impact that man could have on global climate? Why does that question always seem to be met with such unusual hostility?”
It’s a dumb question that’s why. We already know what’s cooking us and the possibility you speak of is unlikely. Look up Occam’s Razor. If it looks like a fish and is wet and slippery like a fish, then it probably isn’t a porcupine. If you are not speaking of an unknown cause of GW and are instead talking about an undiscovered solution (it’s not clear which), then Bob has already answered below, you can start fixing the known problem or you can wait for science fairies who may or may not come.

“As for your comments about solar and wind energy, look we are talking about what the earth’s climate will be like in 2100.”
I say your science fairies are already here and they are called: solar, wind, geothermal, EVs/PHEVs/EREVs, LEDs, and energy storage.
Those are the Ford automobiles or our age. …and we’re going to be driving them because oil is just too expensive to dig up now. Since we’re going to be driving them anyway then let’s get on with it …and no it they are not more expensive they are already dropping below parity in many areas, all except energy storage and it will get there soon.
BTW we are not talking about earth’s climate in 2100, it’s now! We’re talking about the current drought in the USA and across Africa. We’re talking about Katrina and Sandy. We are talking about retreating and disappearing glaciers all over the world. We’re talking about a new Northern Passage were there used to be ice. Open your eyes my friend. …and it will take 20 to 30 years to convert to mostly solar and wind, so it would be good to encourage a faster transition now. The start of this disruptive transition is where we can push it along. After that it will be wild fire burning, like cell phones and PCs.

You seem to be an existentialist. I’m an engineer. You and Rossi keep working on that cold fusion thing and theorizing about unknown natural forces. I’ll be over here installing solar panels and selling EVs/EREVs.

No, that is not an assumption that I make.

A large meteor strike, or a series of meteor strikes could throw up a “sunshade” which would cool off the planet.

In the same way a massive super volcano or a series of
volcanic eruptions (especially close to the equator) could cool off the planet.

A prolonged global nuclear war could cool off the planet, but it’s hard to imagine how a nuclear war could be prolonged. I suspect if one got touched off it would be over in a few days and then a couple of years later the dust would have settled and we’d be back to warming.

I don’t think we should count on any of those known forcing events saving our bacon.

We’re doing something we should not continue to do. We need to change what we are doing rather than rely on something not predicted and totally out of our control.

—

Now, your argument that some new solution might be discovered. That’s different than the earlier argument I think you were making, that global warming might not be due to rising CO2 concentrations, but some yet undiscovered force.

Yes, something new might be discovered. That argument has no merit.

Consider. You are on a small boat in the middle of the ocean and one of your trough-hulls snaps off. Stuff happens. Do you:

1) Start bailing and try to figure out what you can jam in the hole?

2) Sit back and wonder if something else might turn up? You know, a submarine might surface and loan you a pump or a big fish might cruise along and get stuck in the hole. Or something you’ve never heard of before, a truly world unique event might happen.

I’m thinking we should bail….

What the climate scientists are telling us is that if climate change continues to get worse hunger and war will increase. The US military agrees with this finding.

Pollution, obviously coal and oil are two of our largest pollution sources, if not the two largest.

We’ve got immigration problems. If we let the climate change enough to destroy water and food access for hundreds of millions more then the pressure on our boarders will increase.

We’ve got employment problems. A 20 to 40 year program to build a renewable energy system would create a lot of good jobs. Additionally we need to put a lot of people to work making our buildings more efficient/replacing the worst with new very efficient ones.

We’ve got overcrowded highways and airports that need expanding. We could move our medium distance to electrified high speed rail, cut our energy/oil use while making travel cheaper and more comfortable.

We’ve got debt problems. Getting off imported oil and increasing tax revenues by putting more people to work will greatly help our debt problems. Remember, someone who is working not only pays taxes, they don’t cost us unemployment/welfare money.

We’ve got over crowded schools, infrastructure that needs fixing. More tax revenue would fix those problems.

We’ve got crime problems. Fewer unemployed young people would help that problem.

You seem to be attempting to argue that we should wait and see if something totally unforeseen comes along to save us. That, IMHO, would be dumb.
We are in trouble. We have solutions for getting ourselves (largely/somewhat) out of trouble. They work, they are affordable, they have few/minor downsides. We should, IMHO, get moving at warp speed to implement what we have at hand. If a better solution appears a year from now, twenty years from now then we can switch over. In the meantime we will have decreased the amount of CO2 in our atmosphere over doing nothing.
Remember, Henry Ford did not invent the car, the car had been around for many years. Some ran on petroleum, some electricity, and some steam. What Henry did was take an existing alternative to the horse and figure out how to build an affordable version.

Wind and solar have been around for 30 to 50 years. We’ve now figured out how to make them affordable. It’s now time to install and cut back on fossil fuels with the goal of getting >95% of fossil fuels out of our energy stream.

A more accurate way of looking at it would be to compare the scientific knowledge of mankind 100 years ago to the present. Look at the amazing and unimaginable scientific advances that have taken place over that time period. To assume that we are near to knowing all there is to know is the height
of arrogance. Making predictions of the state of the planet and mankind 100 years from now using our current scientific knowledge is absurd.

When we “Fast forward to the early days of the next century” we are taking the present and assuming it will be the same in 100 years. We
have no way of knowing that the billions of dollars we are spending to stop the predicted “poop mountain” will be looked at by people 100 years from now as a total waste.

We have real and present problems with pollution, hunger, war, and a myriad of other issues that could use those billions of dollars. In
my opinion it would make more sense to spend that money on real and present problems rather than wasting it to avoid a prediction generated by computer models that will take place 100 years from now.

But of course, within a few years, nobody rode horses except for sport.”

Correct.

Had we continued to use horses and continued to grow our population we would have had a serious problem. IIRC, there were some 30,000 horses in Chicago doing “taxi” service. Thousands of privately owned horses on top of that, I would assume.

But we changed courses. Away from horses. We dodged the Poop Mountain issue. Henry Ford gave people an option to horses and people changed how they hauled themselves around.

—

Fast forward to the early days of the next century. We’re facing something even worse than Poop Mountain. What science is telling us that if we don’t change course and do it fairly quickly we’re going to cook ourselves.

So, do we keep burning coal, oil and natural gas or do we switch to energy sources which don’t increase the temperature of the planet?

Of course. There is always a possibility that a brand new physical force totally unknown at the present time will be discovered. The real question is how likely it that to happen?

Right now we have a very well confirmed reason for the observed warming. We have know since the 1800s that CO2 allows visible wave length energy (light) but blocks other wave lengths (heat).

We’ve been directly measuring CO2 in the atmosphere since the middle of the last century and find that the increase in CO2 concentration is sufficient to account for the observed warming. We can use techniques such as sampling air trapped in ice cores to measure CO2 levels for many centuries back.

We can determine from the makeup of that CO2 that much of it comes from burned fossil fuels.

Therefore, since we have a “forcing event” that is well measured and well documented, finding two previously unknown physical forces, one which warms the planet and another which neutralizes the blocking force of CO2 becomes a very long shot. I’d say the discovery of either is certainly no more than 1/one billion likely. To get the odds of both multiply 1/one billion times 1/one billion.

We’re talking a very small number. Rick Perry had a better chance of being elected president.

As for your comments about solar and wind energy, look we are talking about what the earth’s climate will be like in 2100. If you asked someone in 1900 what they worried about people in 2000 they would probably say: Where would people get enough horses? And what would they do with all the horse dung? Horse pollution was bad in 1900, think how much worse it would be a century later, with so many more people riding horses.

But of course, within a few years, nobody rode horses except for sport. And in 2000, France was getting 80% of its power from an energy source that was unknown in 1900. People in 1900 didn’t know what an atom was. They didn’t know its structure. They also didn’t know what a radio was, or an airport, or a television, or a computer, or a cell phone, a satellite, an interferon, speed dialing, genes, CDs, airbags, ultrasound, fiber optics, laser surgery, an MRI, ICU, IUD, IBM, IRA, ERA, EEG, EPA, IRS, DOD, PCP, HTML, internet.

Now. You tell me you can predict the world in 2100. Tell me it’s even worth thinking about. Our
models just carry the present into the future.
They’re bound to be wrong. Anyone who gives a moment’s thought knows it.

You could start here –
http://en.wikipedia.org/wiki/Milankovitch_cycles#Present_and_future_conditions
Make sure you pay attention to “anthropogenic effects
may modify or even overwhelm orbital effects”. I’d say we’re way into overwhelm mode.

I am interested in your figuring the earth should be cooling down. One of the questions I’ve had, since watching Gore’s movie a number of years ago, is how wide is that spike? …when should the earth be cooling down? Recent cooling of Northern Hemisphere in response to the historically very long absence of sun spots was very interesting in this respect. Do you have any good links/references on the earth starting into a cooling period by now?

Clearly there are changes in temperature that are not human caused. The Sun warms and cools slightly on an ~11 year cycle. ENSO cycles (which may be driven by the solar cycle) warm and cool the planet. Changes in Earth orbit cause very long scale changes in planet temperature.

Best I can tell we should be cooling toward a distant ice age at the moment left only to “natural” forces.

We’ve not only raised the temperature from what it was at the beginning of the Industrial Revolution (or perhaps since the dawn of rice agriculture), we’ve overridden the natural cooling that was underway.

I’m not saying that I’ve never made a stupid argument, but I can’t put my finger on what offends you in this discussion.

There is very good evidence of human deforestation increasing flooding during wet cycles and reducing water during dry periods. This caused some areas in South-Western North America to become uninhabitable during drought cycles. Trees are amazing in their ability to hold water in the ground. So there are other examples in North America of anthropomorphic damage combining with natural effects to make areas uninhabitable. Do we want to do this to the whole Earth? Well Mr. Jacobson?