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Global Warming Past The Point of No Return
mad_goldfish writes "The UK's Independent is running a front page story today on a scientific report claiming that global warming is now unstoppable, after measuring changes in the level of ice in the arctic." From the article: "The greatest fear is that the Arctic has reached a 'tipping point' beyond which nothing can reverse the continual loss of sea ice and with it the massive land glaciers of Greenland, which will raise sea levels dramatically. Satellites monitoring the Arctic have found that the extent of the sea ice this August has reached its lowest monthly point on record, dipping an unprecedented 18.2 per cent below the long-term average." Either way, someone wins a bet.
Erik the Red started a colony in Greenland back in the AD 900's. http://www.greenland-guide.gl/leif2000/history.htm
According to archealogical records, at time the colony was warm enough to grow crops and support a decent little town. Now, all ice. The region went through an extremely warm spell for a hundred years or so then froze up again. I wonder what the glacier levels where then? I guess we will never know.
Ehh...this is the life we chose.
Volcanos also spit SO2 in addition to CO2, which basically has the opposite effect (it increases albedo). Furthermore, when they erupt, the ash they throw into the atmosphere reflects sunlight to the extent that major eruptions effectively cool down the Earth. When Pinatubo erupted, it lowered the global temperature by a fraction of a degree. When Thera/Santorini erupted about 3600 years ago, the sempervirens trees from California recorded a sharp drop in temperature.
The Raven
You're thinking of the Orontius Finaeus Map of Antarctica from the 1500's.
Hire a Linux system administrator, systems engineer,
Yes, the Earth *has* gone through dramatic climate changes in its history:
Vostok data and others. We also have more recent data from ice, sediment cores which all give the same sort of data: the earth's climate changes wildly naturally, but over many thousands of years.
Two things seriously stand out in all of the data:
1) The earth's temperature *has varied* widely - but over tens of thousands of years. The most pronounced spike was when temperature went from 8 degrees below present 140,000 years ago to 2 degrees above present 125,000 years ago; that's 10 degrees in 15,000 years. We're currently experiencing a change of 0.2 degrees every decade, I.e., thirty times as fast. While there have been shorter spikes that have been steeper, nothing in history even approaches what we're experiencing right now.
2) There is an extreme correlation between CO2 and temperature. There is no doubt about the severity of our CO2 spike, nor its cause. We're injecting at a rapid rate earth's sequestered carbon into the atmosphere, and have 2.5xed atmospheric carbon since the early 1800s. We output about 7.1 billion (of which 3B enters the atmosphere) additional tonnes of carbon per year. The atmosphere currently holds about 750B tonnes (which, as stated previously, is a 2.5x over the early 1800s). While there is hope that marine biota will increase carbon consumption, history has shown that such changes take thousands of years when left unassisted.
regardless of whether we eject terawatts of thermal energy
What on earth does this have to do with global climate change?
A forest fire or volcano is a hell of a lot more energy than humans normally put out
If you want to get back to climate change, their CO2 and methane emissions aren't comparable, except for historic supervolcanoes. At the same time, volcanoes produce overall global cooling because of the aerosols and sulfuric acid particulate (which increases cloud formation).
You look beautiful! Incidentally, my favorite artist is Picasso.
Err, I don't know...maybe the missing ozone layer has something to do with it?
No. Completely wrong. The missing ozone allows UV radiation through, not more heat. Ozone itself is a greenhouse gas and a pollutant.
Note that while ozone is considered a greenhouse gas only in the troposphere, the primary source of tropospheric ozone is stratospheric ozone... which is what the hole is in.
Bottom line is that stratospheric ozone relies on continual production to sustain itself. Certain chemicals (CFCs, for instance) both interfere with production and destroy some existing ozone in the stratosphere. This creates the hole.
Eventually, (surviving) ozone in the stratosphere sinks down into the troposphere, where it becomes a greenhouse gas, and contributes to globabl warming. This process is the biggest contributor to tropospheric ozone.
So, in reality, the ozone destruction is limiting global warming to an extent, though since some CFCs themselves are powerful greenhouse gases, it is not a net reduction.
"Alcohol, Tobacco, Firearms, and Explosives" should be a convenience store, not a government agency.
The Vostock ice cores have given us good temperature and CO2 records for the last 400,000 years, and we see an obvious 100,000 year cycle of glaciation punctuated by brief warm spells, like the one we're in now. We're currently in an ice age that started 50,000,000 years ago. So that's two cycles we know about: the 100 ky glaciation cycle, and the ~300 My ice age cycle. Presumably there are temperature cycles in between those times as well.
The biggest driver for the ice age cycle is geological. Rocks erode, removing CO2 from the atmosphere as part of the chemical reaction involved in weathering, and eventually depositing it on the ocean floors. The ocean floors are subducted, and the CO2 eventually spit out by volcanoes again. Nothing humanity can possibly do regarding CO2 levels will even be noticed by this vast slow cycle. The cycle is self-governing, as glaciation reduces the amount of exposed rock, increasing atmospheric CO2 levels and therefore temperature. This correction would presumably take millions of years, however, no so helpful to humanity.
The cycle that's interesting on our time scale is the 100,000 year cycle. Every 100,000 years or so temperatures spike (usually to higher than they are now, by a bit) and CO2 levels spike, then within 1,000 years or so something forces temperatures and CO2 levels back down. We don't know what that mechanism is, but it must be quite powerful. For some reason when temperatures peaked 10,000 years ago, they stayed warm (it's a little too early in mankind's history to give us the credit for that, but the unnatural warm spell almost certainly allowed us to develop civilization outside of the tropics).
What mechanism usually cranks CO2 levels and temperatures down when they spike every 100,000 years? Why didn't it happen 10,000 years ago? When will it eventually kick in? Without knowing the answers to these questions, it's just absurd to announce that global warming is "unstoppable". We have only the most shallow hypotheses about how the cycle works in the first place.
Socialism: a lie told by totalitarians and believed by fools.
100,000 year cycle of glaciation
;)
:)
Apparently I missed 10,000 years between the start of the industrial revolution and now, when we've experienced the degree of CO2 increase and temperature rise.
Are you trying to claim that the rates are comparable? If not, then what kind of argument are you trying to make? "The earth has changed before, so 30x-ing the rate won't make a difference"?
within a thousand years
I think you need to look at those graphs again. Historically, temperature changes relatively little over a thousand years, except in modern times.
eventually spit out by volcanoes again
Human CO2 emissions far outpace volcanic emissions. We mine Earth's carbon resevoirs at a tremendous rate - burning about 6 gigatonnes (6e12 kg) (plus an additional GT from displaced carbon sinks) annually. To put that number in perspective, if the carbon sources that we burn annually averaged the density of water, they would fill a cube 1.8 kilometers on each side.
You look beautiful! Incidentally, my favorite artist is Picasso.
Although global climate might be within plausible variation, here's one undisputed fact of human effects. We have royally mucked up the atmosphere.
For at least the past 400000+ years, global CO2 concentrations fluctuated solidly in the 180-300ppm range. Methane flucutated 300-700ppb on a matching path, and both correlate strongly with temperature (r about .8) over that time.
Today, CO2 has shot up to 380ppm and methane above 1700ppb. Any rational observer should conclude this is A Bad Thing(tm).
BTW, we're currently towards the high end of average temperature, not low. What is the phrase "still coming out of an ice age" is being measured against?
Why he is an idiot: http://mustelid.blogspot.com/2005/08/pielke-senior -has-blog.html#comments
He certain has been peer-reviewed, though. The feedback he got from his papers include:
The exchange is not worthy of publication. In fact, I do not understand why P&C even wrote their piece in the first place. They continually destroy whatever point they had in mind by noting Hansen 'did it right'... None of the participants in this pathetic exchange seem to have the slightest clue about the large decadal noise that exists in the oceans and some ocean models.
Which bring up the question about why he resigned, which in his own words:
The current discussion in the media based on the three Science Express articles misses the more significant issue of spatial trends in tropospheric temperature trends.
He quit because the committee was focusing on trends in the global average, and he was more interested in geographical locations.
Realclimate is a group blog focusing only on scientific analysis and which gives no recommendations for policy change. The views they give strike me as typically very cautious - so what do you consider to be alarmism?
Here's one chart of the Vostock data, here's another in a weird movie format that you have to scroll around in, but has some additional data. The commentary on the first page may be BS for all I know, but the charts are good. You've probably seen all this, but many slashotters haven't.
You can see the 100,000 year cycles clearly. Temperatures spike from -8 or -9 degrees (C) below present to 2 or 3 degrees above present in about 5000 years, then almost immediately reverse, dropping about 5 degrees over the next 10,000 years, then cool off slowly over the remainder of the 100,000 year (give or take) cycle.
About 15,000 years ago temps spiked as normal, reaching today's temps about 10,000 years ago but *didn't* dive as would be expected. Humans started messing with the climate significantly only in the past 200 years, but something unprecedented in the 400,000 years of good data we have happened 10,000 years ago - we should have been back to the norm for the Current Ice Age by now. What happened? During the previous cycle CO2 levels stayed at the ~275ppm level for 10,00 years but temperatures dropped nearly 10 degrees during that time anyway - why?
Yes, indeed, as I said repeatedly, the volcanic cycle is far slower than the timescale we care about. But CO2 level changes driven by the big geological cycle dominate the geological data. There have been geological periods when CO2 levels were 6-7 times as high as they are now (we think), but temperatures were about the same. Why? We really know very little about the factors that govern the climate.
What we *do* know is that it's a historical anomaly during the past 50,000,000 years for temperatures to be this warm for even 1,000 years at a stretch - the climate simply isn't naturally stable.
Socialism: a lie told by totalitarians and believed by fools.
First of all, there is no such type of volcanic eruption termed "rhylothetic" (bad spelling nor otherwise). What in God's name are you doing, making up words?
Your choices are: Strombolian, Vulcanian, Vesuvian, Peléan, Hawaiian, Phreatic, and the most powerful, Plinian.
So, maybe your are right. There is no way human pollution can put a dent into the ecosystem the way a rhylothetic eruption can, because there is no such thing as a rhylothetic eruption!
We'll let the rest wonder about the validity of your other fantasy conclusions...
Authority questions you. Return the favor.
>> the acid rain would kill us all by 1990. But I
>> was busy with work and didn't notice the end of
>> everything. How was it?
They actually *did* something about it and mandated pollution controls on coal-fired plants. You were probably too busy with work to notice that too.
400-1200 metric tons per day is absolutely nothing. Humans release 16 million metric tonnes per day (and displace additional absorption). As a long term average, volcanoes produce about 500 million tonnes of CO2 annually, compared to ~6 billion for humans. Furthermore, volcanoes are overall coolers because of the aerosols and sulfuric gasses they release, unlike humans.
You look beautiful! Incidentally, my favorite artist is Picasso.