.jpg)
Posted on 03/19/2014 6:15:30 AM PDT by Mrs. Don-o
400 PPM: What’s Next for a Warming Planet Concentrations of greenhouse gases in the atmosphere have reached this level for the first time in millions of years. What does this portend? »
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.
Who would read that?
CO2 is a trailing indicator, right?
As measured NEXT TO A VOLCANO!
Yinz all catch that?
Also that CO2 concentration is cyclical.
Yes, different words same thought.
Plus, one has to question the accuracy of measurement equipment from 1958.............................
Oh, darn. Hate it when that happens.
"...and the CO2 level was between 2000 and 8000 ppm."
And here I was, hoping that just by exhaling prodigiously, I could bring on my Pliocene Paradise.
Yeah, except for a few pliocene-predators
Oh, it was pleasant alright!
uh 0’, looks like the government will have to switch from preventing homes being built at ocean edges to preventing them from being built on calderas
Scientific American was wonderful when I took it back in the ‘70s. Honest science, interesting articles tamed somewhat for the lay person.
I recently took a subscription and was horrified to discover that it is almost completely tainted, biased with political correctness. It is close to the antithesis of the scientific method, complete with “the science is settled” nonsense.
The magazine’s title is now a joke.
It’s embarrassing that this is what passes for science these days. Shameful.
CO2 readings from the top of a volcano and Antarctica.
Did these people not notice that volcanos spew CO2 and Antarctica has no plant life?
What’s next? Planting sensors in orbit or underwater?
Looks like someone found one...
400 parts per million. That's 1 part in 2,500. That's 4/100ths of 1 percent.
Let's go a little further...
In 1958, when the Mauna Loa site - that is a volcano, right? - started collecting data, the numbers averaged 315 ppm. Now (I'll round up) we're roughly at 400 ppm. That's a difference of 85 ppm - in 56 years.
So somehow a change of 1 part in 11,764 over 5+ decades (0.0085%) is responsible for all this gloom and doom? I'm hardly versed in the atmospheric sciences, but I'd need somebody to explain this to me.
oh no!
you finally found the answer to al bore’s rants-
it is all the “earth hippies and Green peace activists”
building COMPOST piles!- they are the ones that started
this climate change! let’s have Al lock them up.
attempted humor. :)
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.