Radar Map of Buried Mars Layers Confirms Climate Cycles 114
Matt_dk writes "A radar instrument on the Mars Reconnaissance Orbiter has essentially looked below the surface of the Red Planet's north-polar ice cap, and found data to confirm theoretical models of Martian climate swings during the past few million years. The new, three-dimensional map using 358 radar observations provides a cross-sectional view of the north-polar layered deposits. 'The radar has been giving us spectacular results,' said Jeffrey Plaut of JPL, a member of the science team for the Shallow Radar instrument. 'We have mapped continuous underground layers in three dimensions across a vast area.'"
Re:Global Warming (Score:5, Informative)
The newspeak term for that now is "global climate change".
A re-education officer will be along shortly to your location.
Actually, that term was widely held in contempt by the scientific community until it was noted that the term "global warming" actually confuses the issue because climate change doesn't evenly modify the temperature of our climate. In fact, some areas of the globe have cooled of late, but that has little bearing on the global mean temperatures, nor on the localized warming in key areas such as the Arctic. So, much as you may not like the political origins of the term, there's a reason that the media AND the scientific community is using it so widely, now.
Re:Gratuitous Global Warming Comment (Score:5, Informative)
No true believers are required.
Unlike the Earth (which has a big Moon to anchor things), Mars has huge variations [imcce.fr] in insolation due to its obliquity and eccentricity cycles. These oscillations drive large variations in climate, which causes the cool layering [arizona.edu] in the Martian Polar Caps - the so called North Polar Layered Deposits [arizona.edu]. There are lots [arizona.edu] of cool pictures [arizona.edu] of these layers.
While it is true that both the Earth and Mars would exhibit climate changes if the solar luminosity changed, so far I have not heard of any evidence requiring this from Mars. Mars's internal and orbital dynamics are quite enough to keep the climate modelers busy.
Re:Doesn't Speak to Climate Change Here on Earth (Score:2, Informative)
Sure. [www.ipcc.ch]
Interesting. That's not a citation, merely a pointer to an organisation whose mandate it is to report on climate change. From your link:
The preparation of the AR5 pursues the overall mandate of the Panel, the main activity of which is to prepare at regular intervals of five to seven years comprehensive assessment reports about climate change.
If this were mandate by Bush & Co., /.ers would be all over it, pointing out, and rightfully so, that an organisation whose mandate it is to report on something necessarily has a vested interest in it, because if the underlying item being reported on went away or proved fraudulent, then the organisation would also go away.
That said, the URL you point to doesn't actually have evidence itself, though another link on the same site might. As far as a citation for the above claim is concerned, this does not qualify. Please try again, though.
Re:Gratuitous Global Warming Comment (Score:3, Informative)
There are several hypotheses regarding the warming observed on Mars and Pluto [newscientist.com].
Re:Gratuitous Global Warming Comment (Score:5, Informative)
First, you are aware that the solar output (Solar Constant) has been measured since the 1970's ? There is no need to look at distant worlds to see if it is changing - it varies around at about the 0.1 % level [nasa.gov].
Second, I would not put any weight on observations of any body we have not observed for more than one orbit - and that includes Pluto and (for climate) Titan. These are not simple bodies.
The general cause of Pluto's warming is well known - a highly elliptical orbit, and it's near (just past) perigee, where it outgases Methane into the atmosphere. That's one of the motivations behind Pluto Express (to get there while there is still a bigger atmosphere). It is staying warm past perigee, but we have no idea if that is normal or not. Similarly, Titan is passing through the equinox (just as we are here on Earth), and that is causing seasonal change. We know that's happening; we have no idea if what we are seeing is normal or not.
Jupiter is so different from the Earth or Mars that I wouldn't use it as an analogy for anything terrestrial, good or bad. (For example, it generates more heat internally than it gets from the Sun.) Having said that, I had not heard of any warming reported there, so a link would be welcomed.
wrong (Score:3, Informative)
Um, this is the arctic. When you melt that ice, the sea level will remain unchanged.
false. There is a density difference between salt water and 'regular' frozen water. The fact that you don't even know this basic 101 level science really disqualifies you from having any real interpretation of the facts.
Get some sea wter, put it o a glace add some ice cubes and mark the line. See where it is after it melts.
"But, again, we need to talk about significance."
as well as every glacier on the planet.
It doesn't take much of a rise to be significant.
And you link is suspicious. It has a graph that ONLY indicate volcanoes that happen before a cooling, but ignores every other major eruption.
You do understand they climatologist know about the normal cycles?
Re:Doesn't Speak to Climate Change Here on Earth (Score:3, Informative)
Re:Doesn't Speak to Climate Change Here on Earth (Score:3, Informative)
That first graph utterly contradicts all other sources I've seen. I highly doubt its accuracy.
As to the second graph, the scale is so compressed that it's very difficult to see that the current warming trend over the past several decades is an order of magnitude faster than past warming. A warming of a few degrees Celsius over 200 years would appear as a vertical line (literally one pixel wide on that bit-mapped graph!), as opposed to the lines with obvious, albeit steep, slopes.
The bottom line is that the warming we've seen in the past several decades is unprecedented in its rate of change. It's also in line with the warming that was predicted by Arrhenius [wikipedia.org] over 100 years ago and by the Jason committee [timesonline.co.uk] in 1979.
When sea ice melts, it does not change the sea level. Obviously, Miller was referring to ice that is on land. There's lots of ice in the Arctic that is on land, for example, in Greenland, Canada, Russia, and Alaska. The sea level has been rising due to melting ice sheets and the thermal expansion of the ocean. Within the next century, rising sea level is predicted to inundate a number of urban areas.
Re:Global Warming (Score:1, Informative)
The reason why consensus forms in the first place is usually because of evidence. It doesn't always end up being right, but for every consensus overturned by a daring rebel, there are probably 100 that boringly end up being correct after all. Because scientists didn't come to a consensus for the hell of it, they came to one because the evidence was persuasive to most of the people working on the problem.
(And the objection wasn't simply "obviously big things can't move". It was because nobody, including the inventor of the continental drift theory, could work out a mechanism for less-dense continents to move through more-dense oceanic crust. Also, the new seafloor evidence for drift came in 1947 and then throughout the 1950s, not just starting in 1957.)
P.S. It's "anthropogenic", not "anthropomorphic".