World Bank envisions a +4°C future
arstechnica.com
arstechnica.com
Based on what?
I grant you that many posters - even here - think that the science is uncertain or that the economics of trying to prevent it as opposed to deal with it are other than the press suggests.
...but I find it utterly wrong to say that people are not aware of the topic.
1. Believe that human-caused increases in CO2 cause catastrophic climate change. 2. Therefore, anyone who doesn't agree doesn't know about climate change.
2) Having read a bunch of blog posts does not mean knowing about climate change. Herbal supplement and alternative medicine believers also have a vibrant community of email newsletters and advertorial magazines.
- "Climate has always changed." check. - "I live in a cold place, I welcome warming." check. - "We can just adjust." check.
Maybe check if your insightful argument has actually already been debunked here: http://www.skepticalscience.com/argument.php
> "Models are unreliable" Models successfully reproduce temperatures since 1900 globally, by land, in the air and the ocean.
There are many aspects to climate change that you need to convince somebody of who doesn't believe in it:
* The climate is in fact changing
* The CO2 levels in the atmosphere are rising
* The CO2 levels in the atmosphere are rising because of human activity
* The rising CO2 levels cause global warming
* Climate change is a bad thing
* Human produced CO2 does not have a short term effect that can be absorbed by CO2 sinks in nature
* It's economically sensible to take action
While there is extremely good evidence for some of these points there isn't as good evidence for all of them as some people would have you believe.
IMO simple graphs like this (http://www.skepticalscience.com/images/co2_10000_years.gif) are far more convincing than complicated climate models that can be fitted to historical data. Having seen first hand how easily conclusions can be drawn without good evidence due to biases and faulty methods in science I have very little confidence in them until proven otherwise. Once climate models start to consistently predict considerably more accurately than simple curve extrapolations it's best to leave them out of climate change arguments.
Not to rain on anyone's parade, but that's what my Geography teacher taught me and my class ~20 years ago (the general discussion was related to the Quaternary, Jurassic and all that), when I was in 6th or 7th grade, long before all this Climate Change talk. If it matters, he was very passionate about Geology in particular (my teacher was).
It's not all about politics and religion.
It's about the rate of that change and the effects of that change. There's a whole lot elided in the excuse that the climate has always changed: after all, the KT event didn't involve an asteroid bouncing around and hitting every dinosaur.
The reality is that every set of global warming predictions so far has understated the actual amount of warning observed. Models are giving too much weight to long-term stable trends over the recent data, plus scientists don't want to be tarred as "kooks" for having the most extreme projections. So if their model says 5C increase, it's probably low to start off with and it will be lowered more before publication, and it will end up underpredicting warming.
When you read about X or Y amount of warming, it's most likely to be a minimum, not a "most likely" and certainly not a maximum.
Current global warming observed has exceeded the absolute maximums predicted in previous generations of warming predictions.
You're also getting a skewed view. Climate change posts on HN always drive out the people with the strongest opinions: an actual poll of HNers would likely have them supporting the consensus position.
Scientists that have to lie to us for our own good. Now that's Science!
This is a worst case scenario. It even goes as far as stating it may not be possible to prevent and simply lists possible outcomes; climate science is not exact.
So what do I take away from it? Nothing much. Its nothing we haven't seen before, most predictions are being pushed far enough out so they cannot be invalidated.
If the temperature does change as drastically as they suggest why do they think we would not be adjusting as well? A lot can happen in the span of two or three generations. New technologies can minimize if not eliminate the effects.
Look, we went through scares of overrunning the planet with people, mass starvation and disease were to be rampant but it didn't happen, we simply grew into our new existence and population numbers. We certainly can grow into most changes to the planet. Until the change is drastic enough to end life on this planet we will adjust to it. I do not think short of nuclear war we can even engineer that.
1) "overrunning the planet with people, mass starvation and disease were to be rampant"
These were never consensus viewpoints. Anthropogenic climate change, in the low to mid single degrees Celsius, is.
2) There's a whole lot wrapped up in the word adjusting. If it's to mean anything more than "survive" (as a species--many individuals' lives would be cut short), it has to include an active component.
We "adapted" to the ozone hole. Yes, that involved new technologies and habits like better sunscreen and norms around using it. But it also involved people getting together and banning substances that contributed to the problem. That made individual-level adaption much less costly than it would have been otherwise.
We have evolved under natural selection pressures to maximise our exploitation of the world around us - the winning apes were those that could make bigger & sharper tools, bigger fires, bigger farms. The idea that mankind has somehow veered away from the 'natural' path, that he is a 'disease' (the Matrix's Agent Smith), could not be further from the truth. Every organism competing in Earth's biosphere is trying to maximise their resource usage, maximise their mastery over the environment.
Our problem is that we have succeeded! We have grown to dominate the entire planet, and (Elon Musk notwithstanding) that's a hard limit. So we have what Iain Banks calls an 'outside context problem'. The strategies our genes have evolved over eons are now insufficient: there is no more competition between Man and anyone else. Even the competition of one human tribe against another is lessening, now that the big tribes have nuclear weapons.
Solving this problem will require post-Darwinian strategies. Getting to the point where that is a realistic prospect will be highly non-trivial.
I mean those sulphur breathing bacteria which we oxygenated out of existence are utterly pissed at us now.
For those who don't get my comment: we don't know how the planet works. Don't know what our impact is. Oh and the climate changes anyway without our intervention which may cause our demise or not - just go with the flow.
But we know quite a lot about how the planet works and what our impact is. We don't know everything, but we know a lot more than nothing.
It's like sending a blind person over a busy road. If you do it when the pedestrian light is red, you might not know which car might hit her at what velocity, but you know that the outcome is quite likely much much worse than if you wait for the green light.
It's more like we're arrogant blind fundamentalist religious zealots with not much data playing whack-a-mole in the dark and simultaneously fucking everyone in the process.
It's true that climate is complicated and there are significant uncertainties in how they might interact. Most of those uncertainties, however, lie in the positive direction. That's part of the reason why the expected mean warming is much closer to the lower bound than the upper one.
But what's also strange in your argument, you say that if we know less about the effects, then we should freely change the climate system more.
Here's a free online book by Spencer Weart of the history of climate science for anyone who is interested: http://www.aip.org/history/climate/simple.htm
And a blog by Steve Easterbrook about the current state of software in the more complex models: http://www.easterbrook.ca/steve/?p=2828
Probably many software-oriented people here might find the latter blog interesting: "We found that the climate models all have very low defect densities compared to well-known, similarly sized open-source projects."
what's most perplexing for me is the constant pressure on growth. we can't have growth and survive this century at the same time. the big question is the mode of failure of humanity, which at the moment doesn't give reasons for optimism - we're on our way to wars for fuel first, and a couple of decades later wars for food and water.
recommended reading: the limits to growth - http://en.wikipedia.org/wiki/The_Limits_to_Growth
I don't have any doubt of humanity's survival as a species - even a total catastrophe, say a 75% reduction in food production, isn't going to wipe us out. The survival of our current civilization, on the other hand...
We banned CFCs.
The fastest Cray in 1990 could do (I think) 60 GFlops when loaded with 32 processors, which is roughly the sustained GFlops as a high end i7.
So clearly it is not a case of "just need a faster supercomputer and we will have an accurate prediction".
Reality is, from what I can tell, is that we don't have an accurate mathematical model of all the pieces that go into global climate to run on a supercomputer, no matter how powerful. ===
No one challenged me and I got several upvotes and follow-on posts in agreement. link: http://news.ycombinator.com/item?id=4761364
Did something change in the meantime?
Also, if you are going to use "No one challenged me and I got several upvotes and follow-on posts in agreement" as a pseudo appeal to authority, I don't think that the readership of a Hacker News comments section really qualifies as authority on this particular issue.
Edit: Oh, apparently models have already predicted temperatures since 1900 correctly via hindcasting, along with changes in climates after significant events such as the eruption of Mount Pinatubo. And so far, they seem to be on-track with empirical data: http://www.skepticalscience.com/images/SLR_models_obs.gif, though I fully understand if you want to discard that graph due to it's source; the risk of selection bias is very high when taking a shallow look at a large and deep subject.
We do not understand even the basics. For instance, we do not fully understand how the Gulf Stream works.
The problem is that we can't just sum or multiply the uncertainty values and try to arrive at a consensus.
Perhaps an analogy can be made to trying to model the US or Europe's financial system - clearly even the largest banks, spending large amounts of money on IT systems and modeling over the past number of years, have grossly mis-calculated things. And the financial world is arguably less dynamic than Earth's climate system.
I know that the 4 degrees are supposed to be an average, but that statement sounds pretty unbelievable nonetheless.
So, forget about what you've learned about weather and expect the worst and multiply this by two. In other words our uncontrolled experiments with the atmosphere do not lead to a weather upgrade, it is more of a system change - introducing bugs and BSODs.
But on a serious note, this is a worst case analysis and one area when people say rising oceans is that recently in many area's they have gone down. Oceans are like stock it seems! Now alot of these studies also do not factor in land rising and sinking and the effect that has along with even measureing the global water tables on land.
But weather is alot like finance as it is chaotic (ok less predictable over time) and with that maybe th World bank are suited to analyse such things with some authority. But also as with finance, the level of prediction you can make does not mean you can change.
So with that weather can effect finance, but finance can not effect weather. People do in part effect the weather and finance effects people. Its just a vicious circle of people, weather, finance.
Even at a relatively low population density equivalent to that of Los Angeles, you could fit the entire population of the world 3.4 times over in the contiguous United States.
Agriculture is a potential problem, but technological advances are improving the situation. If everyone switched to vastly more efficient plant-based diets, it wouldn't be a problem at all.
Migrations and property destructions will matter too. If New York gets a even bigger Sandy a few times every year, the rest of USA will too suffer economically.
Global temperatures have a long-term cycle of about 12 degrees C. We're at a peak, so indeed it seems temperatures have been going up for a while. Now it's time for them to come back down. http://ctdonath.blogspot.com/2012/02/global-climate-change-i...
Climate changes. Cope.
Sure, but to the transition will take money (effort) and time. And already food supply if a finely tuned system with not much margin for error.
I'm sure your argument is that: well, on the scale of hundreds of thousands of years, you can see temperatures vary on that scale! Sure. But we are talking about anthropogenic climate change. Even the worst case scenario--which everyone agrees would be bad and people spend a whole lot of effort arguing it can't happen because of that--would barely show up on the graphs you linked.
So they're of little value, and I recommend you take them down because of how they might be construed to mislead.
Indeed we are. I put those graphs up precisely to show that the anthropogenic changes are mere noise in the natural order of climate change, regardless of scale. I contend that the dismissal of such historical context is intended to mislead.
Even if the average temperature is the same, the amount of food you can produce can vary a lot.
An LA without water is just a desert. Whatever combination of desalination, increased air conditioning, and migration ends up being done to mitigate the effects of climate change is expensive. Really expensive.
Unfortunately, many people who are loathe to interfere with the economy via the government are all too happy to decide that they know enough about Caribbean fisheries, rice paddy cultivation in Burma, and civil infrastructure in Doha to say that a government policy that will likely significantly and adversely affect all of them is fine.
I guess that if there's no war and the infrastructure is intact (just inadequate), you can do that in even less time.
Let's give an analogy: if you push a button, you have a 50% chance of losing your house. Do you do it, since "just as well, nothing might happen"? 30%?
Often, stability has a lot of value by itself.
In reality it's like 50%, nothing happens; 25%, climate becomes slightly better (why won't it?); 25%, climate becomes slightly worse. So why bother a lot now? We could be dead in dozens of fun ways even without climate change.
http://climatechange.worldbank.org/sites/default/files/Turn_...
which was a dead link for me the first few times I tried to follow the link, but is working fine as I type this.
The World Bank report was "written by a team from the Potsdam Institute for Climate Impact Research and Climate Analytics, including Hans Joachim Schellnhuber, William Hare, Olivia Serdeczny, Sophie Adams" and other co-authors. Other scientists and commentators reviewed the report, with acknowledgment from the World Bank, and the bank expressed gratitude to the organization Connect4Climate for contributions to the production of the report.
The Ars Technica article summarizes the report as estimating that even if all countries are able to meet their current emissions pledges there's still a 20 percent chance global average temperatures will rise by 4°C by the end of the century. Predicted sea level rise would be a half-meter or more.
Just last week here on HN another participant shared a speculative essay by science fiction author Charlie Stross on the world 500 years from now. Stross predicted sea-level rise of at least a meter, so I looked up sources about the effect of sea level rise. An interesting series of online maps shows projections of flooded land based on various degrees of sea level rise for places of interest such as New York City,
http://geology.com/sea-level-rise/new-york.shtml
San Francisco,
http://geology.com/sea-level-rise/san-francisco.shtml
the Netherlands and England,
http://geology.com/sea-level-rise/netherlands.shtml
and Chesapeake Bay.
http://geology.com/sea-level-rise/washington.shtml
In all cases, the maps default to showing seven meters of sea level rise and do not project any civil engineering projects to protect existing infrastructure. Having read Matt Ridley's blog post "Go Dutch"
http://www.rationaloptimist.com/blog/go-dutch.aspx
back when it was published, I wonder if the most dire predictions about the Netherlands are true, or if the Netherlands, the land of polders,
http://static.nai.nl/polders/e/index.html
can continue to be "living proof to climate pessimists that dwelling below sea level is no problem if you are prosperous."
The report continues with dire predictions of hot summers and changes in rainfall. "It is my hope that this report shocks us into action," is World Bank President Jim Yong Kim's statement about the report. "Even for those of us already committed to fighting climate change, I hope it causes us to work with much more urgency."
I fully agree with the premise that there will continued widespread use of fossil hydrocarbon fuels for electricity generation, transportation, and building heating. There are no effective incentives in place today, nor any likely in the next few decades, to prevent further consumption of fossil hydrocarbons, and that will surely result in a substantial increase in atmospheric concentration in CO2.
Predicting climate change is a safe prediction any time, because over 100 year and especially 500 year time scales, we have often observed climate change in historic times. Over longer time scales, but since Homo sapiens populated much of the earth, rock art in the Sahara Desert shows that the Sahara was once much less arid than it is now, and cave art in Europe shows that the climate of Europe was once much more frigid than it is now.
I live in the United States Midwest, and my mother grew up in a hotter part of the United States Midwest during the Dust Bowl era. Most of her family is still near the family farm on the windswept Great Plains. I don't expect any part of the earth to become uninhabitably hot. We have, according to the best developed models of influences on world climate, a sure prospect of a generally warmer Earth, warming currently lethally cold areas into areas that will be habitable. My experience living in subtropical east Asia in two long stays about two decades apart suggests that we will have more warming of cold areas than turning hot areas into unbearably hot areas from global warming.
Despite the dire predictions in the World Bank report, it is not necessarily the case that port cities will be inundated even by more substantial sea level rise than is anticipated by the report. New York City is sufficiently prosperous to attract some of the world's brightest minds to live there (I know some young people who have moved there recently) and the current city administration actively encourages making New York City a technology hub. New York will thrive, whatever the climate.
http://abcnews.go.com/blogs/technology/2012/11/new-york-can-...
Venice and New Orleans have been in long-term decline for quite a while, from bad governance, and will surely suffer further relative decline, regardless of sea levels. There will still be a great port at the mouth of the Mississippi-Missouri river system, and it will be a thriving and cosmopolitan city, but it may well be in a different place along the river delta from the current location of New Orleans. Venice may basically vanish, but current ports that matter for the world economy will gain the infrastructure investment to build up protection against the sea faster than the sea will rise.
There is much more interesting content in the long World Bank report referenced in the submitted article, but allow me to explain why I think the high end of global warming predictions (and thus the high end of sea level rise and climate pattern change predictions) is unlikely. We already have a known model for induced global cooling from the "natural experiment" of volcanos erupting and ejecting much dust high into the atmosphere. If the climate change we now experience produces more pain than gain (where I live, at 800 feet above sea level in a continental dry, cold winter climate zone, global warming has so far mostly produced gain), then there will be political and economic incentives to sequester greenhouse gases, or directly shade the Earth with high-altitude dust, or to do whatever else science discovers to slow and perhaps eventually reverse global warming. The end of the century is about eighty-eight years from now, and surely our understanding of climate models and geoengineering possibilities will be stronger then than it is now. Over the time span of the report, I would expect enough of an increase in understanding of climate models to bring about workable means to moderate global warming and shape climate change in the direction of making most inhabited regions better off.
Comment reposts should (must?) designate such at the top with a link back to the original comment.
Certain parts of the world that are low-lying or subject to extremely high temperatures will become uninhabitable. Too bad for those who thought it would be a good idea to settle there, they'll have to migrate.
Once all the ice has melted, sea levels will plateau. By the 22nd Century (notwithstanding a global nuclear war between now and then) we will have mastered nuclear fusion and will no longer be dependent on fossil fuels.
So what's the big deal?
Someone more qualified will hopefully answer you - but I can say for sure that your understanding of the potential consequences is so simplified as to be wildly incorrect.
Unfortunately enough, levels of melting that range from likely to possible will by themselves be very expensive and difficult to deal with.