Grim Picture of Polar Ice-Sheet Loss 412
ananyo writes "A global team of researchers has come up with the most accurate estimate yet for melting of the polar ice sheets, ending decades of uncertainty about whether the sheets will melt further or actually gain mass in the face of climate change. The ice sheets in Greenland and Antarctica are melting at an ever-quickening pace. Since 1992, they have contributed 11 millimeters — or one-fifth — of the total global sea-level rise, say the researchers. The two polar regions are now losing mass three times faster than they were 20 years ago, with Greenland alone now shedding ice at about five times the rate observed in the early 1990s. This latest estimate, published this week in Science, draws on up to 32 years of ice-sheet simulations and 20 years of satellite data to give an estimate two to three times more accurate than that in the last IPCC report."
no rapid melting (Score:2, Informative)
The study excludes suggestions of rapid melting: "Antarctica is not losing ice as rapidly as suggested by many recent studies. What’s more, snowfall in east Antarctica still seems to be compensating for some — but not all — of the melting elsewhere in Antarctica." It generally just seems to confirm what people had been assuming was happening anyway: a modest amount of melting in response to increasing temperatures. Note that melting from ice sheets only accounts for 20% of total sea level rise.
Re:Oh noes! 11 mm in 20 years! (Score:4, Informative)
What percent of 4,000,000,000 is 32? (Score:1, Informative)
Oh my! 32 years and 20 years of monitoring, the melt is unprecedented! After 4 billion years of existence, the Earth is laughing quite heartily at the experts.
Volcanoes aren't a major contributor to CO2 (Score:5, Informative)
it is incredibly foolish to believe that humans are responsible for the melting of the polar icecaps. one volcano eruption puts off more CO2 than all of the emmissions that humans have put out since there were humans.
That statement is factually incorrect. Volcanos do not emit more CO2 than humans-- they emit less, by orders of magnitude.
http://www.agu.org/news/press/pr_archives/2011/2011-22.shtml [agu.org]
http://hvo.wr.usgs.gov/volcanowatch/archive/2007/07_02_15.html [usgs.gov]
http://www.agu.org/pubs/pdf/2011EO240001.pdf [agu.org]
http://www.skepticalscience.com/volcanoes-and-global-warming.htm [skepticalscience.com]
http://www.newscientist.com/article/dn11638-climate-myths-human-co2-emissions-are-too-tiny-to-matter.html [newscientist.com]
From http://news.sciencemag.org/sciencenow/2011/06/scienceshot-volcano-co2-emission.html [sciencemag.org] :
"A popular myth among climate change skeptics is that volcanic emissions of carbon dioxide dwarf those generated by humans. But a new report in today's issue of Eos reveals precisely the opposite: In a mere 2 to 5 days, smokestacks, tailpipes, and other human sources of CO2 spew a year's worth of volcanic emissions of that greenhouse gas. According to the paper, five recent studies suggest that volcanoes worldwide (such as Alaska's Shishaldin, shown) emit, on average, between 130 million and 440 million metric tons of CO2 each year. But in 2010, anthropogenic emissions of the planet-warming gas were estimated to be a whopping 35 billion metric tons. Individual events—such as Mount Pinatubo, whose major eruption in 1991 lasted about 9 hours—can produce CO 2 at the same rate that humans do, but they do so only for short periods of time. It would take more than 700 Mount Pinatubo-sized eruptions over the course of a year to emit as much carbon dioxide as people do, the study notes."
Let me note that it is misinformed statements like this that tend to make real scientists dismiss global-warming deniers as crackpots. If you really want skepticism of anthropogenic global warming to be taken seriously, you need to have a basic understanding of the real world.
Re:My prediction for this discussion (Score:5, Informative)
DNA of trees, plants, and insects including butterflies and spiders from beneath the southern Greenland glacier was estimated to date to 450,000 to 900,000 years ago, according to the remnants retrieved from this long-vanished boreal forest. That view contrasts sharply with the prevailing one that a lush forest of this kind could not have existed in Greenland any later than 2.4 million years ago.
So the most recent time Greenland could have supported significant plant life was 450,000 years ago. More recently than expected, still not recent.
The Wikipedia article does not say that Greenland's climate has changed dramatically many times over the last 100,000 years, it says that ice cores from Greenland have shown that the world's weather and temperature can change rapidly and that this has happened often over the last 100,000 years. This is not a reassuring finding, as it implies that the seemingly stable climate that we've enjoyed over the last few thousand years can change very quickly if pushed.
Yes, we all know that older folk have been ignoring warnings about global warming since the seventies. That's not something to brag about.
Yes, the climate has not been the same and will not remain the same forever. This is not an excuse to continue polluting. All people die sometime, right? So shooting them in the head now doesn't really matter, does it?
Re:Fingers in ears (Score:4, Informative)
Well, while you're technically correct, the terms are there out of today's perceptions, and the meanings are understood as crystal clear, at least by most of us in the US.
Racist...in general means White attitudes towards Blacks or other less Caucasian skin tones. You don't generally hear that Blacks can be racist or act in a racist manner against Whites...it just isn't in the popular vernacular. So, the reverse-racism or reverse-discrimination are understood to mean anti-white attitudes from blacks....for the most part.
Check the numbers [Re:'emmissions' and 'eruptions' (Score:4, Informative)
...Given the fact that 1 eruption can change global climate for several years...
An eruption can change climate for several years... but not due to the emission of greenhouse gasses, which are trivial.
The aerosols from an eruption, however-- the ash and sulfates-- can block sunlight and have a significant cooling effect. This is a very real effect, and making sure that climate models correctly model the effect of historic volcano eruptions is a useful way of verifying the fidelity of climate models.
CO2 emissions from volcanoes on the other hand, are just not significant. It's somewhat hard comprehend the scale of 30 trillion kilograms of carbon dioxide, which is the amount emitted by humans per year, but if you picture a cube of coal about 10km on a side, that will start to give you an idea. This is much larger than the total of what is out by volcanoes, including both eruption and non-eruption emissions.
Water, water everywhere [Re:Volcanoes aren't a...] (Score:5, Informative)
this clearly shows that humans are in no way responsible for global warming.
Unfortunately, it shows nothing of the sort.
It says that water vapor is the most significant greenhouse effect gas. Water vapor indeed is a greenhouse gas, but water vapor cycles in and out of the atmosphere based primarily on temperature. The hotter is is, the more water evaporates into the atmosphere; the colder it is, the more water condenses out of the atmosphere. So, basically, water vapor is an amplifying agent-- if you increase the temperature, more water evaporates, and the greenhouse effect increases. This is well known.
I would like to really suggest you read the IPCC Working-Group 1 report, "The Physical Science Basis of Climate Change" http://www.ipcc.ch/publications_and_data/publications_and_data_reports.shtml [www.ipcc.ch]
You would be able to argue more effectively if you started out by being aware of what is already known.