Is Earth due for a mass extinction?

March 3, 2011

extinction2_h1It has all the signs of a sick good-news/bad-news tale. The bad news is that Earth may be ripe for a mass extinction, where 75 percent or more of the life on the planet vanishes forever.

The good news is it’s unlikely to happen for at least three more centuries.

Scientists writing in the journal Nature warn that we could be on the brink of a mass extinction, the kind of species loss that has happened just five times in the last 540 million years.

“If you look only at the critically endangered mammals–those where the risk of extinction is at least 50 percent within three of their generations–and assume that their time will run out and they will be extinct in 1,000 years, that puts us clearly outside any range of normal and tells us that we are moving into the mass extinction realm,” Anthony Barnosky, an integrative biologist at the University of California at Berkeley said in a statement about the study he co-wrote.

extinction3_h2Are humans to blame? Possibly.

“A modern global mass extinction is a largely unaddressed hazard of climate change and human activities,” said H. Richard Lane of the National Science Foundation, which funded the research.

If the species that are now considered critically endangered, endangered and vulnerable actually went extinct, and that rate of extinction continued, the sixth mass extinction could arrive in three to 22 centuries, Barnosky said.

This is by no means a sure thing, and the scientists said there is still time to save endangered species short of a tipping point. That would require dealing with a perfect storm of threats, including habitat fragmentation, invasive species, disease and global warming.

The last mass extinction was 65 million years ago when a space rock slammed into what is now the Yucatan peninsula, one of several factors that caused the big die-off. Previous events occurred 200 million years ago, 251 million years ago, 359 million years ago and 443 million years ago.

Polar bears are sometimes seen as symbols of endangered species, and in the United States they are listed as threatened under the Endangered Species Act because their icy habitat is melting away. The most recent animal to be designated as extinct by U.S. authorities is the eastern cougar.

Photo credits:  Steven Amstrup, Polar Bears Interational (A female polar bear walks along the shore of Canada’s Hudson Bay, waiting for ice to form in this undated photo)

NASA (A burst of gamma rays reaching Earth may have caused an extinction 440 million years ago)

4 comments

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[...] Source: Reuters [...]

Humans have walked this world off and on for more than 300 million years, some move to the stars, some just give up, some don’t have a chance to make it, we of this day and age can survive if we leave this Earth and go to the stars. We have the resources to achieve living in space and moving to other worlds but to many people have to just survive this world and it’s problems to think about moving to the stars. So people lets get the Governments to work together and get us off this ever moving, ever changing piece of rock!

Posted by LarryDean | Report as abusive

One does not have to be a qualified scientist or have much in the way of formal qualifications to form an opinion and One does not require a lot of knowledge and practical experience to know that any system that is constantly under increasing or suddenly imaginable strain eventually breaks down. As witnessed in world events recently.
Unless the propaganda wars of vested interest stop and people get on with the division of labour that is needed to make this spaceship,Earth,a more self sustaining concern then it the children born after 2020 that my heart goes out too.
With the strands of the present we weave the web of the future and at the moment I see humankind going back to primitive technologies to survuve and exist.

Posted by animatedclay | Report as abusive

the planet earth have no any expiration but the humans does

Posted by chxvilla | Report as abusive

[...] reuters.com Spring Fail – Epic moments of fail, owned & pwn Gnam Gnam – In cucina con fantasia Focus Magazine of SWFL – Southwest Florida regional magazine Related via Categories“Climategate” e-mails rear their ugly heads — again“The Harry Potter theory of climate”Suspected smuggler of rare Sumatran tigers arrested in IndonesiaAppropriately enough, it’s National Tsunami Awareness WeekAn arctic adventure Tags: climate change, Cougar, Environment, extinction, nature, polar bears [...]

[...] put pressure on every other species on Earth. Some scientists believe Earth is on the brink of a sixth mass extinction (the last one was 65 million years ago) and see human activities as being at least partly to [...]

Mass extinction events unfold over tens of thousands of years. Increases in CO2, methane and other hot house gases go part and parcel with mass extinctions. The largest life forms die off first as they cannot withstand the increase in temperatures. Fossil and geologic evidence support these conclusions through every extinction event. The end of the last ice age brought with it the loss of Mammoths, Mastodons, Dire wolves, Smilodon…etc. All the largest genus of their species.

Every major ocean fishery is decline by any where from 40 to better than 80%. Curiously it is not caused simply or in large part by over fishing. Sustained ocean temperatures of 79 degrees Fahrenheit or higher kills coral, the soil of the ocean forest. It has been estimated close to half of all coral reefs have been lost to date.

One can only wonder if we have mental midgets running government or just garden variety sociopaths.

Posted by coyotle | Report as abusive