Link

400 PPM: Carbon Dioxide in the Atmosphere Reaches Prehistoric Levels

10 May

Article from Scientific American by David Biello 

400 PPM: Carbon Dioxide in the Atmosphere Reaches Prehistoric Levels

On May 2, after nightfall shut down photosynthesis for the day in Hawaii,carbon dioxide levels in the atmosphere touched 400 parts-per-million there for the first time in at least 800,000 years. Near the summit of volcanic Mauna Loa—where a member of the Keeling family has kept watch since 1958—sensors measured this record through sunrise the following day. Levels have continued to dance near that benchmark in recent days, registering above 400 ppm for the first time in eons after midnight on May 7. When the measurements started the daily average could be as low as 315 ppm, already up from a pre-industrial average of around 280 ppm.

This measurement is just the hourly average of CO2 levels high in the Hawaiian sky, but this family’s figures carry more weight than those made at other stations in the world as they have faithfully kept the longest record of atmospheric CO2. Arctic weather stations also hit the hourly 400 ppm mark last spring and this one. Regardless, the hourly levels at Mauna Loa will soon drop as spring kicks in across the northern hemisphere, trees budding forth an army of leaves hungrily sucking CO2 out of the sky.

5-2-5-7-2013-mauna-loa

Courtesy of Scripps Institution of Oceanography

It may be next year before the monthly average level reaches 400 ppm—and yet longer still until the annual average reaches that number.

But there is no question that the world continues to inexorably climb toward higher levels of greenhouse gas concentrations. Barring economic recessions, the world may be lucky to stop at 450, 500 or even beyond. Last year, humanity spewed some 36 billion metric tons of greenhouse gases, up from 35 billion the year before.

In the coming year, Scientific American will run an occasional series, “400 ppm,” to examine what this invisible line in the sky means for the global climate, the planet and all the living things on it, including human civilization. Some scientists argue we passed the safe level for greenhouse gas concentrations long ago, pointing to the accelerating impacts, from extreme weather to the meltdown of Arctic sea ice. Others argue that we have yet more room to burn fossil fuels, clear forests and the like—but not much—before catastrophic climate change becomes inescapable. And the international community of nations has agreed that 450 ppm—linked to a rise of 2 degrees Celsius in global average temperatures—should not be exceeded. We are not on track to avoid that limit, whether you prefer the economic analysis of experts like the International Energy Agency or the steady monitoring of mechanical sensors.

The last time CO2 levels at Mauna Loa were this high, Homo sapiens did not live there. In fact, the last time CO2 levels are thought to have been this high was more than 2.5 million years ago, an era known as the Pliocene, when the Canadian Arctic boasted forests instead of icy wastes. The land bridge connecting North America and South America had recently formed. The globe’s temperature averaged about 3 degrees C warmer, and sea level lapped coasts 5 meters or more higher.

co2-levels-over-800000-years

Courtesy of Scripps Institution of Oceanography

The world will change again due to human activity and associated emissions of CO2, perhaps causing another set of coral reef extinctions like those found during the Pliocene, among other impacts. When Charles D. Keeling first started his measurements, CO2 made up some 317 ppm of the air we breathe and climate change was already a concern thanks to the work of John Tyndall, Svante Arrhenius and Guy Callendar. Every year since 1958 the sawtoothed line depicting Keeling’s measurements—readings kept up by his son Ralph—has climbed up, capturing the rise in greenhouse gas concentrations as well as the world’s breath.

keeling-curve

Courtesy of Scripps Institution of Oceanography

What can be done? In the short term, more potent but shorter-lasting greenhouse gas emissions could be curbed or a concerted effort to develop CO2 capture and storage technology could be undertaken. Whether we do that or not, given CO2′s long lifetime in the atmosphere, the world will continue to warm to some extent; at least as much as the 0.8 degree C of warming to date is likely thanks to the CO2 already in the atmosphere.

At present pace, the world could reach 450 ppm in a few short decades. The record notches up another 2 ppm per year at present pace. Human civilization developed and flourished in a geologic era that never saw CO2 concentrations above 300 ppm.We are in novel territory again and we show no signs of slowing to get our bearings, let alone stopping.

Advertisements
Link

De-Extinction: Can Cloning Bring Extinct Species Back to Life?

7 Mar

De-Extinction: Can Cloning Bring Extinct Species Back to Life?

Article from Scientific American

At some point in the next decade, if advances in biotechnology continue on their current path, clones of extinct species such as the passenger pigeon, Tasmanian tiger and wooly mammoth could once again live among us. But cloning lost species—or “de-extinction” as some scientists call it—presents us with myriad ethical, legal and regulatory questions that must be answered, such as which (if any) species should be brought back and whether or not such creatures could be allowed to return to the wild. Such questions are set to be addressed March 15 at TEDx DeExtinction, a day-long event in Washington, D.C., organized by Stewart Brand’s Revive & Restore project. Brand previewed the topics for discussion last week at the TED2013 conference in Long Beach, Calif.

Scientists are actively working on methods and procedures for bringing extinct species back to life, says Ryan Phelan, executive director of Revive & Restore and co-organizer of the TEDx event. “The technology is moving fast. What Stewart and I are trying to do with this meeting is for the first time to allow the public to start thinking about this. We’re going to hear from people who take it quite seriously. De-extinction is going to happen, and the questions are how does it get applied, when does it get used, what are the criteria which are going to be set?”

Cloning extinct species has been tried before—with moderate success. An extinct Pyrenean ibex, or bucardo, (Capra pyrenaica pyrenaica) was born to a surrogate mother goat in 2009, nine years after the last member of its species was killed by a falling tree. The cloned animal lived for just seven minutes. Revive & Restore itself has launched a project to try to resurrect the passenger pigeon, which went extinct in 1914.

Revive & Restore has already held two private workshops for geneticists and others involved in cloning and conservation to share information on current de-extinction projects, techniques and ethics. The upcoming TEDx gathering will be the first public event to widely discuss the same topics. Like all projects organized by Brand’s Long Now Foundation, transparency is a central issue for Revive & Restore (after all, Brand is the man who famously said, “information wants to be free”). “For our organization, the idea of being able to provide this information or the exposure of these ideas, it’s just a way of starting the dialogue,” Phelan says.

Although next week’s meeting will mostly focus on resurrecting lost species, Phelan says the same cloning technologies also have a lot of potential to help species that are currently endangered. “I think we’re going to be able to apply these technologies to species on the brink,” she says. “To me, that’s why I’m most excited about this. How are these technologies going to be used to help improve genetic bottlenecks and things like that?”

Of course, conservation budgets around the world are already strained, and most endangered species do not have any direct conservation funding devoted to them. Wouldn’t focusing on cloning technology take away from those scarce conservation funds? “My knee-jerk reaction to that is simply that it should not be either-or, but that it should be an ‘and’ question,” Phelan says. “I don’t think there’s a certain amount of dollars that can only be spent for helping animals on the brink. I think that these things are additive, and that the challenge is ensuring that conservationists and others that are involved in wildlife are aware of these technologies and can move in directions where they can apply them.”

Speakers at TEDx DeExtinction will include George Church, professor of genetics at Harvard Medical School; Hank Greely, director of the Center for Law and the Biosciences at Stanford Law School; and Oliver Ryder, director of genetics at the San Diego Zoo Institute for Conservation and Research. Tickets are available for the live event, which will also be Webcast for free.

What do you think? Should scientists try to clone and resurrect extinct species? Is it worth the cost or the effort? Do you want to see wooly mammoths walk on Earth again or watch flocks of passenger pigeons black out the sky? Are you encouraged by these technologies’ potential to keep critically endangered species such as thenorthern white rhino from going extinct? Please let us know in the comments.