Study: CO2 buildup could affect food quality

Wheat field in Upper Austria

A wheat field in Upper Austria ripens under a summer sun. bberwyn photo.

Protein levels in key grains could decline by 3 percent

Staff Report

FRISCO — Along with cutting yields of some key crops, increasing atmospheric carbon dioxide is also expected to affect the nutritional quality of food crops. Field tests by UC Davis scientists show that elevated levels of carbon dioxide make it harder for some plants to convert nitrogen into proteins.

“Food quality is declining under the rising levels of atmospheric carbon dioxide that we are experiencing,” said lead author Arnold Bloom, a professor in the Department of Plant Sciences at UC Davis. “Several explanations for this decline have been put forward, but this is the first study to demonstrate that elevated carbon dioxide inhibits the conversion of nitrate into protein in a field-grown crop,” Bloom said. Continue reading

Climate: Methane emissions from freshwater ecosystem set to soar as Earth warms

New study assesses freshwater methane on a global scale

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Microorganisms in freshwater ecosystems generate significant amounts of methane.

Staff Report

FRISCO — After recalculating Earth’s greenhouse gas budget, Princeton scientists say that methane emissions will start increasing at a faster pace than carbon dioxide, primarily due to the release of methane from microscopic freshwater organisms.

Methane is about 30 times more effective than CO2 at trapping the sun’s heat, and for every degree of warming, methane emissions will increase several times over, according to the research published in Nature.

Continue reading

Climate: Permafrost thaw doubles carbon losses

Study says greening tundra won’t offset permafrost meltdown

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Study says new plant growth won’t compensate for carbon emissions from melting tundra in the Arctic. bberwyn photo.

Staff Report

FRISCO — Permafrost could dwindle by 30 to 70 percent by the end of the century, and more vegetation in the Arctic won’t be enough to offset the carbon emissions from thawing organic soils.

Scientists with the Woods Hole Research Center reached their conclusions after a series of field tests designed to measure net gains or losses in carbon emissions. The study is published in the journal Ecology.

“Our results show that while permafrost degradation increased carbon uptake during the growing season, in line with decadal trends of ‘greening’ tundra, warming and permafrost thaw also enhanced winter respiration, which doubled annual carbon losses,” said WHRC assistant scientist Sue Natali. Continue reading

Forest fungi help stabilize climate during low CO2 times

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Yet another study shows how fungi may play a key role in regulating carbon.

By Summit Voice

FRISCO — While most current climate research focuses on increasing levels of carbon dioxide, scientists in the UK recently studied long-past eras when CO2 levels were much lower, and discovered a biological mechanism that could explain how the Earth’s atmospheric carbon dioxide and climate were stabilized over the past 24 million years.

When CO2 levels became too low for plants to grow properly, forests appear to have kept the climate in check by slowing down the removal of carbon dioxide from the atmosphere. The report has been published in Biogeosciences, an open access journal of the European Geosciences Union.

“As CO2 concentrations in the atmosphere fall, the Earth loses its greenhouse effect, which can lead to glacial conditions,” said lead-author Joe Quirk, with the University of Sheffield. “Over the last 24 million years, the geologic conditions were such that atmospheric CO2 could have fallen to very low levels … but it did not drop below a minimum concentration of about 180 to 200 parts per million. Why?” Continue reading

Study outlines greenhouse gas ‘hangover’

Oceans will lose ability to absorb heat

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By Summit Voice

FRISCO — Keeping global warming below 2 degrees Celsius may require a more dramatic turn away from fossil fuels than previously believed, researchers said last week, describing a greenhouse gas lag that could cause temperatures to keep rising even after CO2 emissions stop.

The Princeton-led study, published in the journal Nature Climate Change, suggests that it might take a lot less carbon than previously thought to reach the global temperature increase scientists deem unsafe. Temperatures would initially drop after CO2 levels stabilize, but eventually, the world’s oceans would lose some their capacity to take up heat, especially in polar regions, the study found.

In their study, the scientists modeled a scenario that halted all CO2 emissions after 1.8 billion tons carbon entered the atmosphere, a simulation often used to measure the staying power of heat-trapping gases. The model shows that oceans and forests would absorb about 40 percent of the CO2 within 40 years and 80 percent after 1,000 years. Continue reading

Global warming: Tiniest plankton to thrive with increased CO2, upsetting ocean carbon cycle

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Evidence is growing that increasing levels of CO2 are going to have a fundamental impact on ocean plankton.

Changes likely to reduce oceans’ capacity to absorb carbon dioxide

By Summit Voice

FRISCO — In the great global warming experiment there will be winners and losers, and it looks like some of the tiniest plankton species will be among the winners — probably at the expense of larger species higher up the food chain.

Research off the coast of Svalbard, Norway in 2010 showed that the smallest plankton groups thrive at elevated carbon dioxide levels.

This could cause an imbalance in the food web as well as a decrease ocean CO2 uptake, an important regulator of global climate. The results of the study have been published in Biogeosciences, a journal of the European Geosciences Union. Continue reading

Climate: Researchers report startling rate of acidification in parts of the Arctic Ocean

‘Nowhere on Earth have we documented such large scale, rapid ocean acidification’

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Researchers with the NASA-funded ICESCAPE Mission explore freshwater melt ponds in the Arctic. Photo courtesy NASA Earth Observatory.

By Summit Voice

FRISCO — The steady decline of Arctic sea is speeding ocean acidification, researchers reported this week in PLoS One, describing their findings after extensive water sampling in the region.

“A remarkable 20 percent of the Canadian Basin has become more corrosive to carbonate minerals in an unprecedented short period of time. Nowhere on Earth have we documented such large scale, rapid ocean acidification,” said lead researcher and ocean acidification project chief, U.S. Geological Survey oceanographer Lisa Robbins.

The research showed that the rapid pace of sea ice decline may be contributing directly to increasing acidification by exposing more of the ocean to atmospheric carbon dioxide. The impacts are intensified further by the diluting effect of melting ice. The freshwater further lowers pH levels and reducing the concentrations of calcium and carbonate, which may impact the growth of organisms that many species rely on for food. Continue reading

Study challenges forest carbon cycle assumptions

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Forests alone won’t be able to soak up all the excess heat-trapping carbon dioxide in the atmosphere. bberwyn photo.

‘Nature cannot self-correct entirely against climate change …’

By Summit Voice

FRISCO — Massive reforestation efforts may help soak up a small part of the carbon dioxide generated by fossil fuel combustion, but it’s not a panacea for increasing concentrations of heat-trapping greenhouse gases.

Most widely accepted climate models have probably been over-estimating the ability of forests to absorb carbon from the atmosphere because the models do not represent the responses of soil microorganisms correctly, according to scientists with Northern Arizona University.

Their 11-year study showed that, contrary to expectations, high CO2 levels didn’t significantly increase carbon uptake. Plants did contain more carbon when CO2 levels were increased, but the soil actually lost carbon due to microbial decomposition; both factors essentially balanced one another out. Continue reading

Climate: Study of Mediterranean volcanic vents shows what increasingly acidic oceans may look like

Higher CO2 levels reduce biodiversity

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What’s the future of our oceans? Bob Berwyn photo.

By Summit Voice

FRISCO — Studying volcanic vents near the Italian coast has helped scientists gain a glimpse of how increasingly acidic waters could impoverish ecosystems by reducing biodiversity. The study focused in differing levels of acidity around the vents, where carbon dioxide gas bubbles into the water naturally.

“The background, low-grade stress caused by ocean acidification can cause a whole shift in the ecosystem so that everything is dominated by the same plants, which tend to be turf algae,” said lead author Kristy Kroeker, a postdoctoral researcher at the Bodega Marine Laboratory at UC Davis. Continue reading

How will CO2 affect keystone ocean species?

global warming ocean changes

How will rising levels of CO2 affect ocean chemistry?

Research tracks impact on bacteria that support the ocean food chain

By Summit Voice

FRISCO — Increasing carbon dioxide concentrations could change fundamental elements of the ocean food chain by weeding out certain organisms, according to a new study that took a close look at how bacteria may respond to changing ocean chemistry.

The research is part of broad effort to see if there will be climate change winners and losers. The new study, published June 30 in Nature Geoscience, helps identify which ocean organisms will thrive and which will perish in the environment of tomorrow.

The findings suggest that global warming will have huge effects on nitrogen-fixing cyanobacteria (bacteria that obtain energy through photosynthesis, or “blue-green algae”), with implications for every living thing in the ocean. Nitrogen-fixing is when certain special organisms like cyanobacteria convert inert – and therefore unusable – nitrogen gas from the air into a reactive form that the majority of other living beings need to survive. Without nitrogen fixers, life in the ocean could not survive for long. Continue reading

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