> What makes the whole conversation unproductive is there appears to be two sides: one which argues there is no problem and we must do nothing, and the other side says that the problem is going to end the world as we know it and we must change our entire way of living and make it our number one priority.

This is called a false dichotomy. There are an entire range of viewpoints on this; you've just chosen two extremes to work from.

Some public people have been trying to clarify that the world won't end, it will just be a far more miserable place to live. Fortunately, we have the smog problem in Beijing to point to as a very easy example of what to expect from population centers that don't make efforts to control pollution.

Further, there aren't just the effects of warming to consider, but lots of other environmental concerns too, like overfished oceans and oil spill disasters.

Earth won't end. Earth will get along just fine without us.

> Is the world warming? I think it most certainly is, but I would also note that it appears that the warming trend has halted for the past 10 to 20 years.

It hasn't. There was a "missing heat" problem, that has since been largely resolved by finding quite a bit of warming in the deep ocean. IIRC that study is still pending further research, but seems solid. If it's true, then that's a fairly bad sign, since ocean temperature is a lagging indicator -- i.e., it'll continue to stay warm long after the atmosphere has begun to cool.

http://phys.org/news/2013-07-decade-unprecedented-deep-ocean..., "Past decade saw unprecedented warming in the deep ocean"

> Is the warming man-made? To a large degree, I believe that it is. However, there are a lot of things that we don't understand about climate (solar cycles, effects of water vapor, ocean CO2 sequestration, etc.)

And, of course, the thermodynamics of the increasing numbers of UFOs and spectral spirits.

Seriously, though, the problem here is that, first, those factors have been looked at (although I'll agree that they could benefit from further study -- but so could everything) and they have been found not to be influential, and second, there's no evidence to think in the first place that they should be influential. That is, climate change denialists are running from rebuttal to rebuttal as each one is disproven, despite the overwhelming evidence that scientists do already know what the causes of warming are over the last few centuries.

For example: http://www.ed.ac.uk/news/2013/sun-221213, "Sun not a key driver of climate change"; http://climate.nasa.gov/evidence/, "Climate change: How do we know?"; http://www.skepticalscience.com/argument.php, "Global Warming & Climate Change Myths" (answers 174 common climate change denialist myths).

> If I had to put a number on it, I would say 50 to 60% man-made.

This is a made-up number. It is meaningless.

> Can we do anything about it?

Absolutely. Lots of people have been doing things about it. For example, U.S. energy consumption has leveled off over the last decade, despite an explosion in personal electronics, thanks to increases in efficiency in everything from cars to energy production to the devices themselves.

And every little bit helps.

> This is where I begin to separate from the global warming crowd.

Er, with all due respect, you separated from the global warming crowd quite a while back in your comment.

> Theoretically, we can certainly do something about it, but having worked in government I just don't see any practical way that we can reduce greenhouse emissions to such an extent that it's going to make a great difference.

"I can't make a really big difference, so I won't make a difference at all."

California added more residential solar in 2013 than in all previous years -- combined. Is that not a difference? Countries around the world have been building out renewable energy. Germany is now 25% renewable in energy production; Sweden has become so efficient at converting trash into energy that they're now importing trash from other countries.

Certainly, not being able to make some impossibly large positive difference in emissions isn't an excuse for continuing to make the problem worse, which is what denialists want.

> Further, china and India are ramping up their CO2 emissions, and there's nothing that the developed countries can do about it.

"My neighbor doesn't maintain his yard, so I shouldn't bother to maintain mine."

As the rest of the world continues to move forward in improved environmental technology, there will be increased incentives for China and India to do so too. There will be more political pressure, but the technology will also improve and become cheaper, as it has been for decades. At some point, it will simply make economic and political sense for India, China, and other countries to adopt better environmental technologies.

> Finally, I have ethical objections to telling developed countries that they have to use less energy which will inevitably result in more lives lost due to starvation or simply just malnutrition and poverty.

This is ... a very silly thing to say.

Nobody's calling for energy or food reductions that will reduce populations. On the contrary, continuing to improve energy technology, as well as agriculture and education and medicine, will increase the life expectancy for a population, and, based on all available metrics so far, as people live longer, better educated, healthier lives, they naturally choose to have fewer babies.

What do you think the life expectancy is for the residents of all of the squatters' villages in the Pacific islands that have been destroyed by hurricanes and other storms?

Are you really advocating for continuing the use of old, wasteful technology which, as a side effect, increases the likelihood of devastating storm seasons, because it's better for poor people?

> Should we do anything about it? I believe this is a cost-benefit analysis. And I haven't done the analysis myself, but sometimes I question whether spending the enormous amounts of money today is worth putting off an uncertain disaster tomorrow when we have actual problems today that we could be working on instead.

Alright, look, you're not questioning anything. You're daydreaming. We live in an age of unprecedented access to information. When I was little, we had encyclopedias and public libraries; if I wanted to learn about a subject, I had to put in a lot more effort than is necessary today.

You could choose to spend just a few minutes here and there actually questioning all of this, and you could learn something and then you could have all of the benefits of a slightly more informed opinion, rather than just repeating the political talking points you've heard elsewhere.

And, by the way, climate is an actual problem that we do have today.

> We have millions of people every year dying from malnutrition

...and the technology to feed them, were it not for all of the navel-gazers wondering whether or not we should...

> ...poor water supplies...

...I've personally raised funds to send a hydrologist to Uganda...

> ...malaria...

...Bill & Melinda Gates Foundation...

> ...HIV/AIDS...

...tremendous amounts of ongoing research, to the extent that there now exist very low impact, long-term, cost-effective treatments for HIV/AIDS...

> ...etc.

So why do you believe that any of these things has to stop while we build more solar plants or work on further increasing vehicle efficiencies?

> Why not save those actual lives instead of spending the money saving hypothetical lives in 100 years.

Are you talking hypothetically, or practically? Is this a choice that you, personally, actually have to make, ever?

Why don't you visit https://watsi.org/fund-treatments (a YC non-profit), and make a difference in an actual life there, and then come back and opine a little bit more about whether or not we should entirely abandon environmental R&D?

> And indeed, won't we be more suited to save those lines in 100 years than we are right now, meaning that the mitigation effort could be a lot cheaper?

I fully expect that, 100 years from now, people will be having the exact same conversations, in some form or another, that they've been having for the last thousand years: "really, what use is it to do anything at all, if we have to choose between doing one thing or doing another thing?"