Global Warming?

[ELKCHSR]

If the effects of man are so devestating to the planet, I wonder what this did?
Why is the atmosphere still here?
I would bet this thing heated the earth up far more than a couple few degrees, and look, we are here and thriving...

Ancient Impact Turned Part of Earth Inside-Out

By Robert Roy Britt
Senior Science Writer, SPACE.com

A space rock the size of a large mountain hit 1.8 billion years ago and dredged up part of Earth's lower crust, essentially turning a bit of the planet inside out, a new study concludes.

Earth's upper crust is about 22 miles thick. Scientists have debated how deeply into the crust the shock wave from a large asteroid could penetrate. All the way to the next layer, it appears.

The evidence comes from a crater in Sudbury, Ontario. Most of the crater was long ago folded into the planet or eroded away. But a section is exposed, revealing minerals and other features that can be compared to more recent craters that are more intact. From all this, scientists gleaned clues to the catastrophic impact.

It appears an asteroid about 6 miles wide hit the planet at more than 89,000 mph.

"The impact punched a hole to the very base of the crust and the meteorite itself was probably vaporized," said University of Toronto geologist James Mungall, who led the study. Much of the heating and damage is done by a shock wave that compresses material ahead of the impacting object.

A plume of superheated rock from deep down surged upward and landed on top of the impact site, creating the melt layer visible today.

In a telephone interview, Mungall explained that in the top layers of the Sudbury structure, his team found relatively high concentrations of iron, nickel and platinum, stuff that is more common in the lower crust of the planet than in the upper crust (the elements exist in just trace amounts in both regions). The lower crust sits atop Earth's mantle, which surrounds the core.

"Since it ended up on top, it effectively inverted the layering of the crust," he said. "It had not really been appreciated that large impacts would selectively move material from the bottom of the crust up to the top."

The top layers were also relatively depleted of zirconium, uranium and other elements that tend to show up in other impact sites that only involved melting of the upper crust.

The results were detailed in the June 3 issue of the journal Nature.

Mungall's team also found an enrichment of iridium in the overlying layer at the Sudbury complex, which was already thought to be part of an impact crater. Iridium is commonly associated with extraterrestrial rocks and is a strong indicator of an impact. The crater was initially more than 125 miles wide.

The study was funded in part by the Ontario Geological Survey and the Geological Survey of Canada.

 

[Oak]

Ok, let's not worry about what we're doing to the planet now, because it will be as good as new in 1.8 billion years.

 

[ELKCHSR]

Yea, I didn't think that far ahead, that just may work, but we have had many large space debri hit this ball of mud since...

 

[Wapiti Slayer]

Here's one I read today.

Scientist: Climate changes could hurt Idaho's farms, fish
Resources panel considers what expert has to say

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Related Links
Climate Impacts Groups at UW
Rocky Barker

The Idaho Statesman | Edition Date: 06-04-2004
Idaho's snowpack could drop by 35 percent over the next 50 years, worsening the state water shortage, one of the nation's top climate scientists told a legislative committee Thursday.

Temperatures that are expected to rise, on average, 7 degrees over those five decades will reduce the amount of snow in lower elevations, including the mountain ranges around Boise, said Philip Mote, a University of Washington climate scientist.

That could make it harder to store water in reservoirs and reduce the natural recharge of the expansive Snake River Plain Aquifer that provides water for much of southern Idaho. In a state where dairies, fish farmers and cities are fighting over limited water supplies, the changes could hurt Idaho's economy. Salmon also could face more challenges.

Some changes, predicted by models accepted by a consensus of scientists, are already apparent, Mote said.

"Most of the West has seen an increase in March flows just as the models predict," Mote told the Idaho Legislature's 36-member Expanded Resources Interim Committee looking at water issues statewide.

Mote spoke to an audience of lawmakers, water experts and lawyers that was largely skeptical about human-caused global warming. The consensus of scientists, Mote said, is that humans are changing the global climate by dramatically increasing the concentration of carbon dioxide and other gases in the atmosphere.

These gases trap the heat of the earth like a greenhouse.

"I've never really bought on big to the whole global warming theory," said Sen. Dean Cameron, R- Rupert. "But I was impressed by the way he laid out the evidence."

Mote said allowing more flexibility in spring river management could aid Idaho and other Northwest states in addressing the changing snowfall and rain patterns he predicts. "We'd have less concern for flood control and more concern on keeping reservoirs full in the summer," he said.

Rep. Scott Bedke, R-Oakley, a cattle rancher, said Mote's predictions support farmers' call for building more reservoirs and raising the level of existing dams.

"If indeed these changes are in our future, then I think it speaks for increased storage," Bedke said.

Rep. Doug Jones, R-Filer, said the early snow melt this year was largely lost. "We look at this year, we thought we were in good shape until March," Jones said.

Mote said the current drought can't be tied by the data to global warming. But the trends show that the human-caused warming has changed nature since 1960.

Several lawmakers asked about the impact on endangered stocks of salmon in the Northwest. Mote said it would affect salmon differently during their life cycle. In some streams, flooding will increase, scouring out eggs at critical times.

In other places, high temperatures and lower stream levels will hurt fish in the summer.

"There will be some stocks of salmon that will have a difficult time with global warming," Mote said.

 

[ELKCHSR]

What was it that made the Anasazi abandon their dwellings (theory any way) in the 12th century. One of the biggest reasons I should state, since there were a few reasons....
It could have been a cyclic global warming? Or was it created by to much human activity? I wonder if that time was worse by far than it is right now? I never realized that this earth has ever sat stable for very long any where on it's entire surface, any time in any history...