industrial architecture -> industrial agriculture

But the longer we wait to take that action the higher the cost.

In different words, you agree that it is all about financial tradeoffs.

You can't ignore the non-quantifiable impacts just because you can't put a number on them.

All the impacts you have been worried about are quantifiable: flooding, destruction of arable land, etc., and the IPCC did put numbers on them. You can't double-count those impacts by saying they don't cost much, but they are civilization threatening nonetheless. If they were civilization threatening, they would have a high cost associated with them and the IPCC would have incorporated them into the cost model, even with a high uncertainty.

What causes habitat destruction if it's not economic development?

Large populations without economic development cause environmental destruction, because they slash and burn for agriculture, use forests for firewood, hunt species to extinction, and reproduce faster, etc. Given the same population size, more economic development results in less environmental destruction and less population growth. That's why allocating our resources to economic development is more important than allocating it to preventing AGW.

Without fresh water in the form of precipitation or irrigation, without fertilizers, without energy to run the machinery and without good soil yields would drop precipitously.

I'm aware of that, and I stand by my statement, since any of those can be obtained with energy and AGW does not threaten the energy supply. Furthermore, the IPCC report itself is clear about North American and European industrial architecture not being threatened by AGW, so, frankly, what are you talking about?

You argued that civilization may be doomed because of destruction of agriculture because of AGW. I have yet to see any plausible argument supporting that view.

I have never argued that this will be an extinction level event for homo sapiens

That's what this thread has been about. If you're arguing about something else, you're arguing about a straw man.

What facts do you have to back up your supposition that at worst "we're talking about a modest reduction in GDP"? I would consider that on the margins of the best case scenario.

It's not a "supposition", it's the conclusion of the last IPCC report after accounting for all the factors with quantifiable economic impact. Furthermore, you want to convince others to act, so you need to provide convincing arguments for your positions; the default action is to do nothing.

But it will lead to the extinction of a lot of other species who are unable to adapt to the rate of change which will make our lives poorer.

True, but the primary cause of man-made extinctions isn't AGW, it's population growth and habitat destruction, and those are related to lack of economic development. Strong measures to prevent AGW are going to make those problems worse by reducing economic growth (IPCC), not better.

It's possible it could be an extinction level event for our technological civilization though. The more time you spend on simply surviving the less time you have for higher level thinking and working on things that aren't necessary for your survival.

How is AGW supposed to cause this? Modern industrial agriculture depends on little more than sun, warmth, and land (freshwater, minerals, and oil make it more efficient, but aren't necessary). How is AGW threatening any of these inputs? All studies and predictions (IPCC etc.) talk about modest increases and decreases in productivity, with Europe and North America largely being a wash overall. As far as modern Western agriculture is concerned, AGW is a non-issue.

I'm curious as to what argument was demolished? During the last maxima a lot of species went extinct, all significant change cause extinctions. That some thrived doesn't disprove that others went extinct.

The original discussion was about extinction of humans. Humans survive in environments from the desert to the arctic, eating pretty much anything that's available. There is no realistically possible degree of climate change that would cause humans to go extinct on earth.

When that argument failed, you tried to side-track the argument by talking about extinction of species and mass extinctions. "Mass extinction" sounds scary, but doesn't matter much to human survival. These days, most of our food comes from a few domesticated plant and animal species in simple ecologies that we control. All we need for food production is sun, water, and space.

Of course, while not threatening to human survival, extinctions are undesirable because they reduce quality of life. Extinctions due to human activities are primarily due to overfishing, pollution, and habitat destruction, ultimately rooted in poverty and overpopulation. Reducing greenhouse gas emissions won't address those problems, it will aggravate them by slowing economic development.

What you are missing is that there is no such thing as being "done" with map data. It's an ongoing effort, with data changing all the time. Google is at the plateau where they are probably as good as it is realistic to be. Apple only has to reach the same level where Google is, while Google is essentially at a static position.

Google is doing indoor maps, maps, streetview and navigation in the most inaccessible places in the world, integration of data from a huge user community, plus search results, plus business data, plus its social network. How is that "a static position"? And how is Apple going to catch up, with no social network, a smaller user community, no search engine?

In at time when there was no penitentiary system the guilty either had to pay with money or blood

Leviticus was written down around 500-300 BC, a time when Greek civilization was at its high point, when the Maurya dynasty rose in India and made religious tolerance and public health care the law, when Egyptian and Persian civilization had existed for millennia. Civilized people at the time lived in great cities with art, theater, palaces, public works, codes of law, judges, lawyers, traders, accountants, restaurants, night clubs, artisans, scribes, apothecaries, priests, monks, and all the other accoutrements of civilization.

The society that wrote down Leviticus, in comparison, was a band of backwards desert nomads that had missed the boat on civilization.

No it is not. If the ice on greenland melts the sea level rise is over 7m.

That would take centuries no matter what happens with climate change.

If a vulcano breaks out below greenland and all the ice drops into the ocean over a few years time span, you have the 7m instantly.

That has nothing to do with global warming and is completely outside our control. Furthermore, subglacial volcanoes are common and don't cause rapid, massive melting of entire ice caps.

Even with "normal" temperature increase like we see right now, it wont take 100 years to rise the sea more than a meter. During the next 100 years it is indeed very likely that most of Greenland will melt.

There is no realistic scenario under which Greenland's ice cover will melt this century.

http://www.ipcc.ch/publications_and_data/ar4/wg1/en/tssts-5-2.html

Of course it has happened before:

http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event

The great majority of species of fish survived, as did almost all mammalian species.

A PETM-like maximum would have a huge impact, to be sure, but it wouldn't cause humans or mammals to go extinct, as the GPPs claimed.

When permafrost melts it is not instantly ready for agriculture and make take a century or more to become ready.

True, but temperatures aren't rising overnight anyway, and even if they did, it would mean a temporary reduction in arable land, not a permanent one. Your arguments about day lengths and topsoil don't support your horror scenarios of "extinction level events" and "collapse of civilization".

It wouldn't shock me if all of the climate disruption reduced human population by half by 2100 but I won't live long enough to see it

That's not an "extinction level event" or even a "civilization ending event", that's 1960s population levels. And that could also happen due to a pandemic or other causes we have no control over.

Under the most contrived, hypothetical climate change scenarios, we might be looking at a few centuries of "dark ages" while human societies rearrange themselves. Under any realistic climate change scenario, we're talking about a modest reduction in GDP. Talking about "extinction level events" and "collapse of civilization" is pure FUD, unsupported by fact.

What a fascinating mix of outright lies, exaggerations, and straw men.

Last time there was a 6C increase 95% of all species went extinct. Some survived and thrived, most didn't.

There has never been a mass extinction where "95% of all species went extinct".

http://en.wikipedia.org/wiki/Extinction_event

Neither land mammals nor humans are going to go extinct even if the polar ice caps melt completely and we have another Eocene maximum. We know that because mammals and primates didn't go extinct last time this happened, they thrived.

We have never had rapid global average temperature change of 10C

Fascinating: you have your argument demolished, and you immediately shift to some other scenario.

Not all previous climates on earth would be compatible with a complex human society like we have today.

Indeed. A snowball earth would be really bad, for example. Even glaciation of the form we had 30000 years ago would be really bad. Any of the warm climate earth has experienced over the last 65 million years is compatible with mammals, people, and complex societies, as we can see from the rich plant and animal life that existed over the entire period.

A 4C increase could very easily become a deal breaker for our civilization. A 10C increase would almost certainly mean the extinction of nearly all currently living species of mammal.

That's nothing but fear mongering without any evidence to back it up; from all we know about Earth's climate history, those statements are false.

"Increase the risks and costs somewhat" doesn't even begin to cover the risk we are taking by not addressing this

We can't "address it". The carbon is already in the atmosphere, and it ain't gonna come out for a long term. And we ain't gonna stop emitting; all anybody is talking about is capping emissions at recent levels. Whatever anthropogenic warming is going to happen is going to happen; all politicians are talking about is whether it happens a few years slower or faster.

* Collapse of sea-based proteins caused by:
        - water acidification, caused by increased CO2 in the water

This has happened before; it doesn't lead to an extinction of land-based animals, and it doesn't even lead to significant extinction of higher animals in the oceans. All that goes extinct is calcareous animals, and they come back when pH drops again. Not a big deal. This has happened many times before.

- over-fishing

Overfishing is a disgusting abuse of the marine environment, but it has nothing to do with climate change.

* Destruction of arable land, caused by:
        - Increase in temperature directly
        - Deforestation - causing soil erosion
        - Increased atmospheric energy leading to more extreme weather, both increase in droughts and storms
        - Flooding caused by sea level rise

On balance, arable land isn't destroyed by climate change, it merely moves around. In fact, arable land may well increase due to climate change, with huge areas of Europe, Siberia, Canada, and Alaska thawing and becoming arable.

Depending on how bad it gets, a significant portion of the worlds food production could collapse in a matter of years.

It "could" do that for many reasons other than climate change. It also doesn't cause extinctions of homo sapiens because rapid, abrupt climate change has happened many times since homo sapiens evolved and we didn't go extinct. Furthermore, sea level rise simply cannot happen abruptly, no matter what the temperatures do; it's physically impossible.

Other reports recently suggests a best case scenario of +4C temperature increase, and worse case in the 8-10C range. The later is likely extinction level changes.

Neither land mammals nor humans are going to go extinct even if the polar ice caps melt completely and we have another Eocene maximum. We know that because mammals and primates didn't go extinct last time this happened, they thrived.

The climate on this planet just isn't stable; it has never been and never will be. Anthropogenic carbon emissions are pushing the climate in a particular direction and arguably may increase risks and costs somewhat. It's worth thinking about that and it's worth talking about, although there's not much that can be done about it anyway.

But the kind of FUD and language like "extinction level changes" and "nightmare world" are unscientific, unjustified drivel and fear mongering.

Yeah, it's not like New York City recently experienced severe flooding or something causing at least $60 billion worth of damage, killing a few people, and basically shutting the whole place down for days.

So? New York City is built on the ocean; flooding and hurricanes come with the territory and have been having for as long as people have been living there. Climate change and sea level rise will make them a bit more frequent over the next century. That's not a "nightmare world".

As far as how much of a sea level rise is really really bad, see for yourself:
http://geology.com/sea-level-rise/

That web page points to a 7m rise by default, a completely unreasonable scenario for centuries. IPCC predictions were 0.5-1m in the worst case; even with the adjustments from the article, maybe that goes up to 0.75-1.5m over the next century. Furthermore, it is nonsense to take an elevation map and project flooding from it; sea level rise and flooding don't work that way.

And it's not like we have a choice: sea level rise has been going on for thousands of years, and it's continuing steadily no matter what we do. With an enormous effort, we may be able to slow it down slightly, nothing more.

Engineering doesn't mean just putting in safety margins that make people happy, it means making cost/benefit tradeoffs. And it means taking into account opportunity costs.

Expending too many resources on reducing green house gas emissions may mean that, in the long run, far more people may die than if we had done nothing.

"Unless we reduce our carbon pollution rapidly, this study clearly shows we are heading for the nightmare world at the top end of the IPCC predictions,"

No, we'll simply be heading for a world with sea levels that are a few feet higher and temperatures that are a few degrees higher a century from now, ample time to adapt without much effort. It's not like we need to move New York or Miami overnight.

Is that a large hadron, or are you just happy to see me?