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Antarctic Ice Loss Big Enough To Cause Measurable Shift In Earth's Gravity
An anonymous reader writes: Contrary to what we were sometimes taught in high school physics, the Earth's gravity is not constant. It actually shows slight variations on different parts of the Earth's surface, and the variations correlate with the density of the material on that surface. The European Space Agency has been measuring gravity for four years, mapping these variations and recording the changes those variations have undergone. Its data indicates "a significant decrease [in gravity] in the region of Antarctica where land ice is melting fastest. Further analysis is, of course, planned so that the whole of Antarctica can be taken into account and "the clearest picture yet of the pace of global warming" can be determined on that continent.
I can't speak for all country, but in France you are taught 1) that gravity constant used varies and we get the values at equators, pole, (iirc 9.78 to 9.83 while we used 9.81) and our lattitude, altitude
2) but afterward to make it simpler we always assume it is a constant because we do not have the math tool to integrate with g(r,theta, rho) over complex surface.
At no point we were taught that gravity is a constant. What we were taught is to use it as constant in simplified problems. That is a difference. I would wagger it is the samer in the country of the submitter, only he missed the important semantic difference.
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The problem is that this is not intended or presented as a proof of climate change. It is merely measuring recent gravitational changes showing the affect of the reduction in ice. The article does pre-suppose that any melting of ice would be the result of climate change. You could certainly argue against that assumption.
But what you can't argue against is the fact that the ice is melting at all, although that doesn't stop some people here from cherry-picking one particular type of ice (sea ice), saying that it has expanded as if that is the complete argument against the total ice loss.
Ladies and gentlemen, the Gish Gallop.
In complete denial of the FACT that Antarctic sea ice is at the HIGHEST LEVEL in decades, these Global warming cult members keep spreading the blatantly false propaganda.
Does the expansion of sea ice mean that the total volume of sea and land ice has gone up? Does it even mean that the volume of sea ice has gone up or is it just being spread thin?
You have cherry-picked a single variable that has gone up and ignored the bigger picture, and then made the outrageous claim that it is the people who actually measure the total ice that are spreading false propaganda.
Answer one question: has the volume of land ice gone up or down? If the answer is down, why is it so unimportant for you to mention this inconvenient fact?
On second thoughts, we can ask an even easier question. Has the total volume of ice gone up or down? According to the article, the gravitational measurements show that it has gone down. Why are you in complete denial of this FACT?
What conclusions are we supposed to draw from that? Well, other than that you don't know the difference between "land" and "sea".
I'm getting tired of hearing about how all life on Earth will end in a few years unless we vote for just one political party and their pet doomsday cult.
I'm sorry that you are getting tired of this, but in this case you can rejoice! Because nowhere in the article did they state such an absurd line.
There is no point making up quotes to get offended by when you could just comment on the actual story at hand. Your entire post has absolutely nothing to do with measuring the gravitational changes of melting ice.
There is no net change. Local gravity becomes weaker where the ice was and stronger where the melted ice now is.
The whole story is. 4 years != climate. Not by anyone's measure. If skeptics tried to debunk AGW on this board with a 4 year trend, everyone would be all over them like white on rice. But 4 years in favor of AGW in the summary? A O K!
Yes but before the ESA satellite there were the GRACE satellites launched in 2002 that also showed West Antarctica losing ice and Antarctica overall is losing ice at a rate of almost 69 GT/year (graph). So it's more like 12 years of data. Even that is a rather short time period compared to the standard climatological period of 30 years. But the standard climatological variables such as temperature, precipitation and wind are very noisy compared the rate of ice loss so it takes longer to discern a significant trend with them than with ice. So 12 years may be long enough for significance. I'm not sure.
The article barks at the wrong tree. The cryosphere page at University of Illinois-Champagne shows that we are currently seeing 1.3 million sq. km more sea ice than the average, and the levels have been sharply rising the last few years.
There is a fine balance between trying to increase awareness and being a downright propagandist. Unfortunately, this article doesn't help the cause. This is exactly the kind of thing that make people believe environmentalists are exaggerating and grasping at straws.
Wired: Stop. You are not helping.
Before you go on you really should learn the difference between ice sheets, ice shelves and sea ice. They are not the same thing. Talking about sea ice in response to this article about the West Antarctic Ice Sheet is a non-sequitur.
1. Global warming = the world getting hotter
2. Climate change = the changes to the climate due to the increased amount of energy due to warming
3. The land ice is melting, causing it to flow into the sea, where some of it re-freezes. It is expected if warming occurs.
4. Volcanoes release between 65 and 319 million tonnes of CO2 per year. Industry releases ~29 billion tonnes per year. So it takes ~19 hours for industry to release as much CO2 as all the volcanoes do per year.
Maybe people will keep "banging the bell" until people like you actually learn what's happening. You suck as a conscientious individual.
The whole story is. 4 years != climate. Not by anyone's measure. If skeptics tried to debunk AGW on this board with a 4 year trend, everyone would be all over them like white on rice. But 4 years in favor of AGW in the summary? A O K!
Not so. The scientific point of view is that the data speak for themselves; different theories try to make sense of the observed data. Theories are never perfect, but we can make theories better by using the scientific method - and this is where the debate invariably breaks down, not because a secretive conspiracy of climate scientists are suppressing facts, but because those suffering from 'skepticemia' are unwilling to accept reality.
Weather is what happens locally, in the short time span - the wind in your hair, the sun on your face - climate is the average of the weather over large areas and long periods of time. So, it is perfectly reasonable to observe that the weather has been unusually cold in Canada this summer, and then say that this goes against the idea of global warming, and the observation requires a theoretical explanation, of course. Climatologists have already given very plausible explanations; the problem is that climate deniers don't want to accept the explanation. But just as it is necessary to consider data that go against the theory, it is also necessary to accept the data that support the theory; hence it is reasonable to state that the loss of icemass in Antarctica supports the theory of global warming.
What I still haven't seen in is just 1 climate model that explains most of the observed current and historical data and doesn't end up concluding that climate change is happening and is caused by human activities. Produce just 1 theory that can stand up the critical efforts of more than a select group of handpicked believers; the truth is that the skeptics are unable to do so, and therefore talk about conspiracies instead. Meanwhile, I think the scientific consensus has moved on, because whether people like it or not, reality keeps happening.
Not exactly and no. When mass is redistributed (due to ice melting, plate tectonics, mantle convection, etc...) the shape of the geoid changes. However the total mass of the Earth is conserved. So if you are far enough away from the Earth to make it indistinguishable from a point mass, Earth's gravity remains constant.