The skies do strange things at the NEEM camp, a remote ice-drilling and research facility on the northern Greenland ice sheet. Midnight sunshine. Low clouds of sparkling ice crystals known as "diamond dust." But when rain fell instead of snow last summer, complete with a rainbow arcing over the camp, the NEEM scientists couldn't believe it. "I've been all over that ice sheet, and to have it rain that far north—that's a shock," says James White, a paleoclimatologist at the University of Colorado who led the American team working alongside those from 13 other countries at NEEM.
It's fitting that part of the NEEM study's fieldwork, which retrieved a two-and-a-half-kilometer shaft of ice, took place during one of the hottest Greenland summers on record. What that ice core has revealed about a warm period 130,000 years ago could be one of the most critical new tools for predicting how our planet will respond to a warmer future.
The NEEM ice core has provided the first picture of the Greenland ice sheet during the entire Eemian interglacial period, a 15,000-year span of natural warming that occurred between the two most recent ice ages. (NEEM is a rough acronym for North Greenland Eemian ice drilling.) During the Eemian, natural variations in Earth's orbit brought the planet closer to the sun, making global mean temperatures up to 2°C warmer than right before the industrial revolution (the Arctic regions were made even warmer, between 3-5°C). That makes the Eemian an especially attractive period for scientists to study, because 2°C of global warming matches the temperature ceiling the UN and other international organizations have established as the limit of tolerable warming during the next century (a limit many climatologists believe we'll meet or even exceed by the end of this century). And what scientists are learning about the Eemian period could be cause for present-day concern.
Based on the study of the paleoclimate record in ice cores as well as the former locations of beaches and coral reefs, researchers believe that the Eemian temperature increase likely pushed global sea levels as high as eight meters (26 feet) above where they are today. That would put many coastal cities deep under water including Miami, the Los Angeles metropolitan area, and large parts of New York [see graphic]. During the Eemian, the polar ice sheets melted over several thousand years; an abrupt increase within the next century—seen by many scientists as inevitable, despite international goals—will not result in a 26-foot rise right away. "Even if you stabilize temperature by 2100, sea levels will keep rising for many centuries after that," says Gavin Schmidt, a NASA climate modeler at the Goddard Institute for Space Studies who specializes in paleoclimate data. The ice sheets will take hundreds of years to fully react to warmer ocean temperatures, he says, "And there won't be very much you can do about it."
The ice core pulled from the NEEM site has discrete, often visible rings, like a tree trunk—each season's snowfall creates a new layer of fresh ice. By studying the chemical makeup of the layers, the NEEM scientists learned both the atmospheric temperature and the ice sheet's height over the years. This data yielded a significant discovery: Previous models had assumed that the Greenland ice sheet was at least half gone at the Eemian's hottest point, but the ice core showed that the sheet's total volume decreased just 25 percent. That meltwater would account for only about two meters of global sea rise, according to Dorthe Dahl-Jensen, a paleoclimate researcher at the University of Copenhagen who led the NEEM project. Therefore, the remaining six meters of water had to come mostly from Earth's other major sea-level "co-conspirator," as James White likes to call it: the Antarctic ice sheet. This new finding suggests that West Antarctic ice is capable of melting far more than previously thought.
An accurate understanding of what was ice at what point in time is a key tool for testing computer models that forecast when, where, and how ice sheets will melt in the future. As data on ancient climates becomes more reliable, scientists can use that data to check their models and improve them.
Just five years ago, such ice-sheet modeling was a "cottage industry," says Schmidt—improvisational at best, inaccurate at worst. In 2007, when the U.N. Intergovernmental Panel on Climate Change (IPCC) released its fourth and most recent assessment report (which guides climate science and policy for the years to come), it projected that sea levels would rise anywhere between 18 and 59 centimeters by 2100—a range that many scientists saw as a poor estimate based on inadequate data. The report inspired paleoclimatologists who study ancient climates and physicists who build climate models to start to collaborate closely, according to Schmidt. "The last report kind of punting on the whole sea level thing has been the driver of an enormous amount of effort in ice-sheet modeling," says Schmidt. "It really was time to step up their game."
Unfortunately, a clearer picture of the future is not necessarily a brighter one. In September, the IPCC will release the science portion of its fifth and latest report, and its sea-level projections for the coming century are expected to increase, based in part on new models of how ice sheets melt. In a field that predicts the future, a little hard data from the past can go a long way.
The bottom line is whether you believe in man made climate change or not, our coastal cities are built on inherently changable lands that will some day be under water. That detracts from the scare tactics, so you won't see it discussed on the tube. I wouldn't worry about it too much though. The way we're going, we have exterminated ourselves by then.
Human induced global warming from the support of world population with the industrial revolution grows climate change.
Another extreme long term push for global warming will be the magnetic polar shift change, which has been happening for the last 300 years. As the magnetic polar shift they lower to almost nothing in reflecting the sun’s rays adding warming to the Earth. For the most part it does not cause extinction from the additional solar rays, because our atmosphere is so thick to filter it out. (Considering the polar change is so gradual there is much debate about it from the science community if it really happens to the extreme or this may be just a minor magnetic change, which will correct itself later. If it is actually happening, there isn't anything the human race can do about it, but just learn to adapt.)
Lastly we always have the cycles of the sun, effecting global weather as well.
The support of the human existance causes an global footprint on planet Earth. Currently the Earth is supporting 7 billion.
"...An international team of scientists has developed crop models to better forecast food production to feed a growing population -- projected to reach 9 billion by mid-century --in the face of climate change...".
The above link is wrong, oopsie, lol.
Here is the correct link.
How Do You Feed Nine Billion People?
We already know what is going to happen, so these continuing studies while interesting, aren't very useful.
The global warming deniers will keep finding sillier and sillier arguments anyway.
Arguments so far:
1) There is no global warming, its a massive conspiracy.
2) Ok, there is local warming/cooling/climate change, but not global.
3) Climate change (aka global warming) is real, but humans cant possibly be the cause.
Reminds me of those people who said the world would end in 2000/2012. Where are those people now I wonder? Maybe they are the ones denying global warming.
@killerT: 22% of Americans believed the world would/might end in 2012. The percentage was MUCH higher for the millennium disaster. In fact, you'd probably find that the people who believed in the Y2K bug are the exact same people that believe in AGW. They believe everything that is fed to them without thinking critically about the problem and forming their own informed opinion.
Climate change absolutely IS real. The Earth has been warming for the last (approx) 12,500 years, which was when the last glacial period ended. Why should we believe that it would have stopped 120 years ago if we hadn't been burning fossil fuels?
We have seen 'huge' increases in CO2. That's the argument from the AGW camp. It is true, we've gone from 280-300 ppm to over 400 ppm, but it's still an insignificant percentage of the atmosphere. And if CO2 was the driver of temperature, shouldn't we have seen a larger increase in temperature? Less than 1 degree C isn't Earth shattering. CO2 is at a higher concentration than it has been in the last 650,000 years according to some sources (Keeling and Whorf). Shouldn't we also see temperatures soaring?
During the Cambrian epoch, CO2 was between 3500 and 7000 ppm. That is 8-17 times higher than it is today and we peaked at around an average global temperature of 25 C. We have one of the lowest concentrations of CO2 in the history of the world right now (which is why Keeling and Whorf only went back 650,000 years with their numbers). Some would say we are CO2 deficient.
Mass hysteria does not mean mass conspiracy. We are very prone to group think. The reality doesn't match what is being told to the public by the media and politicians. If you look at history and what is actually happening right now it is very clear that this is extremely exaggerated and is being used for fear mongering and profiteering. Al Gore owned a carbon exchange company (might still, haven't checked) while he flew around the world in a private jet burning fossil fuel and using many times more energy than the average household. He was in it for money, not for the planet. Why should we believe a word he said?
The anonyme 'ppardee' seems to be incorrectly referring to an event called Paleocene–Eocene Thermal Maximum (PETM)when carbon dioxide levels in air peaked at 7,800 parts per million (ppm), or 0.78%, when it is currently 400 ppm 0.04%. This is 19.5 times higher than the present CO2 level. There CO2 might have been even higher at planetary formation before any life at 400,000 ppm or 40%, but all the high CO2 are speculative quesses and totally irrelevant.
We should be focusing on air before the industrial processes started using up the oxgyen due to combustion processes and tailpipe emission disposal to atmosphere. We need not debate on Saturn's rings to prove that CO2 was higher in the past, nor bother about high methane or carbon dioxide before there were any life, in fact, the very first athmosphere was made of hydrogen and helium when earth condensed from the newborn sun's protoplanetary disk.
Thank you for the additional information. ;)
Well said, Smiddywesson. One indisputable fact from paleoclimate studies is that climate changes over time, both warming and cooling, and oceans rise and fall as water gets locked up in ice sheets then melts. So far it looks like the changes occur over thousands of years; slowly enough that adaptation is possible.
Wonder, I saw the "How Do You Feed Nine Billion People?" article today and laughed. The obvious answer: one person at a time, like we do it today. Another group of researchers creating incorrect global computer models, now of agriculture, to inaccurately inform public policy is just what we need. Somehow people seem to figure out how and where to live and how to feed themselves despite the wisdom of the global modelling scientists.
I think the 25 foot doesn't include places that will be well under water and flooded. Most of the interior of Africa would flood. 25 foot can't be calculated correctly based on coastline simple equation. No one calculated the exact volume of water. It would still be too complex to guess that correctly.
Hope the prognosis is right, and the sea level rise gets a move on. I would like to have a beach front property.
Same article and photos here: climatestate-dot-com/magazine/2013/06/in-ancient-ice-clues-that-scientists-are-underestimating-future-sea-levels/
Feeding 9 billion is an achievable, yes of course. The point is in the process of doing so, how much more CO2 does it put in the enviroment in the process.
like Joan implied I am dazzled that anybody can profit $7249 in four weeks on the computer. have you read this web link Go to site and open Home for details
Making claims about historic climate conditions based solely on circumstantial evidence derived from a small number of ice core samples taken from a single location is basically junk science. There is no way to validate the accuracy of results derived from these 15,00 year old ice core samples.