Turning up the gas

Apr 26, 2011
Sunset on a smoggy summer day in Los Angeles. The discovery of ancient 'hyperthermal' events in Earth's history could help scientists understand how modern global warming could affect the biosphere or Earth. Credit: Barbara Gaitley, JPL image P-48863A

Rapid increases in greenhouse gases have happened more frequently in the Earth’s history than previously realized, according to a Scripps Institution of Oceanography-led study published in the journal Nature.

Scientists have studied extensively the the Palaeocene-Eocene Thermal Maximum (PETM), about 56 million years ago, a period of rapid global warming that’s associated with a temperature spike on par with expectations for today’s global warming scenarios.

But according to the Scripps Institute, there’s been a series of six smaller greenhouse gas fluxes during the same geologic time period (the Palaeocene and Eocene epochs, 65 to 34 million years ago). These so-called “modest hyperthermals” (meaning a rapid, pronounced period of ) had shorter durations and recoveries (about a 40,000 year cycle) and involved an exchange of carbon between surface reservoirs into the atmosphere and then into sediment.

The researchers believe that large-scale carbon releases were vented from the ocean floor, but were reburied relatively quickly.

Under higher CO2 levels, plants take up more toxic materials

Higher concentrations of CO2 in the atmosphere generally increase plant growth and productivity. Plants take up more nutrients from the soil. But according to a new study, they also take up more toxic materials from the soil.

Benjamin Duval from the University of Illinois at Urbana-Champaign and colleagues showed in a paper published in the journal Environmental Science & Technology that contaminants in the soil become increasingly mobile in vegetation and that these toxins could be cycling faster through the ecosystem.

“Plants can’t always distinguish toxic elements from nutrients,” Duval said in a review of his study published in Chemical & Engineering News. “For instance, arsenic can look a lot like phosphorous, which plants need for their metabolism.”

Duval and company collected soil and oak tree samples from a site at the Kennedy Space Center in Florida run by the Smithsonian Environmental Research Center. They measured toxins in samples growing under normal CO2 levels and compared them to those growing at 700 parts per million CO2, roughly double the concentration. They found that concentrations of the 13 metals studied, which included lead, cadmium, and arsenic, among others, were up to twice as high in the plant materials in the elevated CO2 samples.

The researchers point out that the rates are worrisome because the toxic metals may be ingested up the food chain and can depress the decomposition rates of plant litter and hinder soil microbial activity.

The implications for people eating food crops under such a scenario is also troubling. Although, according to Duval, the current uptake of heavy metals didn’t exceed toxic thresholds set by health agencies.

Explore further: The mysteries of Antarctic sea ice

add to favorites email to friend print save as pdf

Related Stories

Reconstructing an ancient climate with algae

Nov 15, 2010

Variations in atmosphere carbon dioxide around 40 million years ago were tightly coupled to changes in global temperature, according to new findings published in the journal Science. The study was led by sci ...

Losing more than we gain from autumn warming in the north

Jan 02, 2008

An international study investigating the carbon sink capacity of northern terrestrial ecosystems discovered that the duration of the net carbon uptake period (CUP) has on average decreased due to warmer autumn temperatures.

Device reveals more about Mars' atmosphere

Oct 12, 2010

Instruments designed by a UT Dallas professor to measure atmospheric components on the surface of Mars have uncovered important clues about the planet’s atmosphere and climate history.

Recommended for you

Tropical Storm Genevieve forms in Eastern Pacific

Jul 25, 2014

The seventh tropical depression of the Eastern Pacific Ocean formed and quickly ramped up to a tropical storm named "Genevieve." NOAA's GOES-West satellite captured an infrared image of the newborn storm ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

omatumr
2.8 / 5 (9) Apr 26, 2011
Thanks for this report.

It is indeed refreshing to read that the journal Nature has published a report from the Scripps Institution of Oceanography admitting that greenhouse gases have happened more frequently in the Earths history than previously realized.

Unfortunately, it will be a long time before confidence is restored in the journal Nature - the journal that published so many "cutting edge" discoveries before government science became a tool of government propaganda.

Anyway another news report today by Dr. David Whitehouse suggests the Sun plays a much greater role than CO2 in causing global climate changes:

http://thegwpf.or...-it.html

With kind regards,
Oliver K. Manuel
Former NASA Principal
Investigator for Apollo