Global warming and environmental irresponsibility are taking a visible toll on natural resources all over the world. Major tourist destinations are not immune.

If you're still undecided about where to travel on this year's summer vacation (presuming gas prices and airfares don't dissuade you from traveling at all), consider some of the following destinations, while you still can. They might look radically different in just a few years' time if we continue on our current courses, and might not be tourist destinations at all.

Snorkel a coral reef
It doesn't matter which one. The National Oceanic and Atmospheric Administration estimates that the world's coral could be extinct within 50 years due to warming ocean temperatures, pollution and ultraviolet radiation among other factors.

But some reefs are in even more acute danger.

Several in the Pacific, including those off of Oahu are under siege from seaweed that has run amok as a result of local people trying to farm it, The New York Times reports.

Caribbean reefs are being undermined by global warming, disease and hurricane damage. In some places, 90% of local reefs have disappeared, according to USA Today.

Take a walk through Yellowstone Park
It's one of 12 national parks in the western U.S. that are undergoing radical changes from shorter, milder winters and other significant environmental pressures, according to a report from the National Resources Defense Council.

Along with Rocky Mountain and Grand Teton national parks, Yellowstone is facing the biggest changes, including shifts in the plant and animal populations as new species invade and squeeze out old ones. Glaciers and snowfields, fishing, winter activities and archeological and historical features are also under threat, making it harder for us to enjoy these great resources that we have at our disposal.

Canoe Lake Tahoe
Appreciate its famous blue hues before it turns murky green. In 1968, the lake's waters were clear to more than 100 feet deep. In 2007, they were clear only to 70 feet, according to the Tahoe Environmental Research Center, at UC-Davis, which has been tracking the change.

As simply as I can explain it, carbon dioxide emissions are crimping oxygen levels in the deepest parts of the lake. This in turn is gradually making it harder for the fish and algae that are crucial to the lake's ecosystem to thrive. No algae, no crystal-blues.

The change has been slowing in the past seven years or so. But UC-Davis scientists are still concerned that the lake could take a turn for the worse in the next 10 to 15 years.

Soak in the Mediterranean sun
The World Wildlife Fund began warning in 2005 that global warming could make Mediterranean countries like Spain, Turkey, Greece and Italy too toasty for even the most ardent sun worshipers in the years to come.

As world temperatures rise, long and frequent heat waves along with droughts and forest fires could discourage people from flocking to what has been the most popular tourism destination on the planet, the group said.

The WWF was looking ahead several years. But anyone who recalls last summer's heat wave -- it was linked to several hundred deaths, plus tourists being evacuated from some areas and stranded in others -- and the heat wave of 2006, will appreciate that this sizzling future might be close at hand.

Explore Patagonia
One of the attractions are its dramatic icebergs. But this mountain region is gradually becoming a soggy lake district instead, as this Greenpeace photo illustrates.

Patagonian Mountain Lake

It's still possible to cruise through this region in Argentina and Chile to see glaciers and their penguin citizenry. But five years ago, NASA was reporting that these ice fields were responsible for 10% of the rise in ocean levels from mountain glaciers, and were melting at an accelerated rate. Patagonia glaciers are of a sort that is more sensitive to climate change than others because of the way they melt, the agency says.

Take a gander at them before tourists need to trade hiking boots for swimsuits.

Visit the Amazon
It isn't climate change that's doing in this Brazilian rainforest and all of its important biodiversity; its industrial farming.

Commercial farming accounts for a small portion of the overall forest loss, but it's responsible for much of the recent clearing as Brazil vies with the US to be the world's largest exporter of soybeans.

Researchers estimate that Brazil accounts for half of the tropical deforestation that occurred between 2000 and 2005. And recent reports estimate that an area roughly the size of Los Angeles was cleared all at once earlier this year.

What do we stand to lose by bending machetes into plowshares? We don't entirely know, and that's the point.

The Amazon is one of the most biodiverse places on the planet. One out of every ten known species in the world lives in the Amazon, and we haven't yet discovered all the plant, animal and insect life that calls it home.

As the rainforest recedes logging, farming and ranching increase pollution while carbon dioxide-scrubbing greenery disappears. We forfeit renewable resources like wood, fruits and vegetables. And plants that are, or could be, the source of new pharmaceuticals disappear.

Camp out in the Arctic National Wildlife Refuge
President Bush is dying to open it up to oil companies for drilling. Environmentalist groups like the National Resources Defense Council have so far managed to keep him at bay, but in case he gets his way, head north now for some camping, hiking or river running.

The refuge hosts 36 fish species, 36 land mammals, nine marine mammals, and more than 160 migratory and resident birds spread across five distinct ecological regions, according to the US Fish and Wildlife Service. Drilling here is only a temporary fix to our fuel problems but the damage to the region and its populace will be permanent,

And besides, those moose, caribou, swans and polar bears just won't look as magnificent if you have to photograph them with an oil rig in the distance.
Eileen P. Gunn writes about the business of life and is the author of "Your Career Is An Extreme Sport." You can learn more about her at her Web site.