Does Short Term GeoEngineering Really Help With Climate Change?

Disentangling the effects of CO2 and short-lived climate forcer mitigation

Authors:

Rogelj et al

Abstract:

Anthropogenic global warming is driven by emissions of a wide variety of radiative forcers ranging from very short-lived climate forcers (SLCFs), like black carbon, to very long-lived, like CO2. These species are often released from common sources and are therefore intricately linked. However, for reasons of simplification, this CO2–SLCF linkage was often disregarded in long-term projections of earlier studies. Here we explicitly account for CO2–SLCF linkages and show that the short- and long-term climate effects of many SLCF measures consistently become smaller in scenarios that keep warming to below 2 °C relative to preindustrial levels. Although long-term mitigation of methane and hydrofluorocarbons are integral parts of 2 °C scenarios, early action on these species mainly influences near-term temperatures and brings small benefits for limiting maximum warming relative to comparable reductions taking place later. Furthermore, we find that maximum 21st-century warming in 2 °C-consistent scenarios is largely unaffected by additional black-carbon-related measures because key emission sources are already phased-out through CO2 mitigation. Our study demonstrates the importance of coherently considering CO2–SLCF coevolutions. Failing to do so leads to strongly and consistently overestimating the effect of SLCF measures in climate stabilization scenarios. Our results reinforce that SLCF measures are to be considered complementary rather than a substitute for early and stringent CO2 mitigation. Near-term SLCF measures do not allow for more time for CO2 mitigation. We disentangle and resolve the distinct benefits across different species and therewith facilitate an integrated strategy for mitigating both short and long-term climate change.

GeoEngineering Cannot Replace CO2 Reduction for Fixing Global Warming

The politically expedient way to mitigate climate change is essentially no way at all, according to a comprehensive new study by University of Chicago climatologist Raymond Pierrehumbert.

Among the climate pollutants humans put into the atmosphere in significant quantities, the effects of carbon dioxide (CO2) are the longest-lived, with effects on climate that extend thousands of years after emissions cease. But finding the political consensus to act on reducing CO2 emissions has been nearly impossible. So there has been a movement to make up for that inaction by reducing emissions of other, shorter-lived gasses, such as methane, hydrofluorocarbons, and nitrous oxide, and particulates such as soot and black carbon, all of which contribute to warming as well.

Pierrehumbert 's study shows that effort to be, as he puts it, a delusion. "Until we do something about CO2, nothing we do about methane or these other things is going to matter much for climate," he said.

Pierrehumbert is the Louis Block Professor in Geophysical Sciences at UChicago, and holder of the King Carl XVI Gustaf Chair in Environmental Sciences at Stockholm University for 2014-2015. His study, published in Annual Review of Earth and Planetary Sciences, brings together findings from the scientific literature with new research and analysis. Its conclusions are clear.

"Ray convincingly shows the benefit and importance of doing everything we can to lower CO2 emissions, and as soon as possible," said Katherine H. Freeman, professor of geosciences at Pennsylvania State University. "We should lower short-lived pollutants like methane too. But, as he makes clear, we should not let them distract us from the urgent need to stop burning fossil fuels."

link.

Pilot Project to Inject Carbon Dioxide Into Basalt for Sequestration

By early August, scientists will have pumped 1,000 tonnes of pure carbon dioxide into porous rock far below the northwestern United States. The goal is to find a permanent home for the carbon dioxide generated by human activities.

Researchers at the US Department of Energy’s Pacific Northwest National Laboratory (PNNL) in Richland, Washington, began the injections into the Columbia River Basalt formation near the town of Wallula on 17 July. The rock contains pores created as many as 16 million years ago, when magma flowed across what is now the Columbia River Basin. Bubbles of CO2 migrated to the edges of the magma as it cooled, forming layers of holes sandwiched between solid rock (see 'Rock steady').

[...]

The Wallula project is the second of two worldwide to target basalt formations, which scientists hope can hold — and permanently mineralize — vast quantities of gas. In basalt, dissolved CO2 should react with calcium and magnesium to form limestone over the course of decades. Until the gas is locked away, the porous basalt layers are capped by solid rock that will prevent leaking. That should eliminate concerns about leakage that have dogged other proposals to store CO2 deep underground, often in sandstone reservoirs.

The basalt reactions are part of a natural weathering process that has helped to regulate atmospheric CO2 levels throughout geological time. Scientists have analysed mineralization in the lab, but it is only now being tested in the field.

Researchers working on the other basalt project, based in Iceland and run by a consortium of US and European scientists along with Reykjavik Energy, made their first CO2 injections last year and will conduct another round this year. Early results look promising, says Juerg Matter, a geochemist at Columbia University’s Lamont-Doherty Earth Observatory in Palisades, New York, who is working on the Iceland project. “The mineralization reaction is most likely faster than what we in the community had thought,” says Matter, who has also contributed to the Wallula project. Assuming that holds true for basalt generally, “you reduce the risk of leakage, and you can pretty much walk away from your storage reservoirs”.

Mitigating Climate Change and Desertification Using Livestock! Yes! Livestock!

Planting Forests Might Mitigate Climate Change Locally

Afforestation, planting trees in an area where there have previously been no trees, can reduce the effect of climate change by cooling temperate regions finds a study in BioMed Central's open access journal Carbon Balance and Management. Afforestation would lead to cooler and wetter summers by the end of this century.

Without check climate change is projected to lead to summer droughts and winter floods across Europe. Using REMO, the regional climate model of the Max Planck Institute for Meteorology, researchers tested what would happen to climate change in 100 years if land currently covered in non-forest vegetation was converted into deciduous forest. This equates to more than a doubling of forest in Poland, Czech Republic, Denmark, Northern Ukraine, Northern Germany and France. But in already heavily forested countries such as Sweden the increase is smaller, at less than 10%.

The large leaf area and low aerodynamic resistance of these types of trees lends itself to enhanced evapotranspiration compared to other vegetation, cooling the surrounding air, and leading to cooler surface temperatures. The model indicates that in the northern part of central Europe and Ukraine afforestation results in 0.3-0.5C decrease in temperature and 10-15% more summer rain by 2071-2090.

The effect of planting trees depends on the environment of each region. Dr Borbála Gálos, who led this study, explained, "While we realize that the amount of afforestation included in our model is unrealistic in practice, even a more modest program of planting trees could theoretically reduce the effect of climate change in Northern Europe. There is less of an effect in more southerly regions due to complex issues including soil moisture content. However, even in these areas, forest cover can provide localized benefits by making the surrounding air moister and cooler, sequestering carbon, protecting biodiversity and air quality, and preventing soil erosion."

Potential for American Biological Carbon Sequestration Increased

A research group has concluded that forests and other terrestrial ecosystems in the lower 48 states can sequester up to 40 percent of the nation’s fossil fuel carbon emissions, a larger amount than previously estimated – unless a drought or other major disturbance occurs.

Widespread droughts, such as those that occurred in 2002 and 2006, can cut the amount of carbon sequestered by about 20 percent, the scientists concluded in a recent study that was supported by the National Science Foundation and U.S. Department of Energy.

The research, published by scientists from 35 institutions in the journal Agricultural and Forest Meteorology, was based on satellite measurements and dozens of environmental observation sites in the AmeriFlux network. Not all of this data had previously been incorporated into earlier estimates, and the new study provides one of the most accurate assessments to date of the nation’s carbon balance.

“With this data it appears that our forests and other vegetation can sequester as much as 40 percent of the carbon emissions in the lower 48 states,” said Beverly Law, a co-author of the study, professor in the Department of Forest Ecosystems and Society at Oregon State University, and science team chair of the AmeriFlux network.

“That’s substantially higher than some previous estimates, which indicated these ecosystems could take up the equivalent of only about 30 percent of emissions or less,” Law said. “There’s still some uncertainty in these data, but it does appear that the terrestrial carbon sink is higher than believed in earlier studies.”

However, the scientists cautioned that major disturbances, such as droughts, wildfires and hurricanes, can all affect the amount of carbon sequestered in a given year. Large droughts that happened twice in the U.S. in the past decade reduced the carbon sink about 20 percent, compared to a normal year.

“With climate change, we may get more extreme or frequent weather events in the future than we had before,” Law said. “About half of the United States was affected by the major droughts in 2002 and 2006, which were unusually severe in their spatial extent and severity. And we’re now learning that this can have significant effects on the amount of carbon sequestered in a given year.”

Carbon dioxide, when released by the burning of fossil fuels, forest fires, or other activities, is a major “greenhouse gas” and factor in global warming. But vegetation, mostly in the form of growing evergreen and deciduous forests, can play an important role in absorbing some of the excess carbon dioxide.

Such information is important to understand global climate issues and develop policies, the researchers noted. This study examined the carbon budget in the U.S. from 2001 to 2006. Also playing a key role in the analysis was the PRISM climate database at OSU, a sophisticated system to monitor weather on a very localized and specific basis.

The period from 2001-06, the researchers noted, had some catastrophic and unusual events, not the least of which was Hurricane Katrina and the massive destruction it caused. It also factored in the 2002 Biscuit Fire in southwest Oregon, one of the largest forest fires in modern U.S. history.

The research found that the temperate forests in the eastern U.S. absorbed carbon mainly because of forest regrowth following the abandonment of agricultural lands, while some areas of the Pacific Northwest assimilated carbon during much of the year because of the region’s mild climate.

Crop lands were not considered in determining the annual magnitude of the U.S. terrestrial carbon sink, because the carbon they absorb each year during growth will be soon released when the crops are harvested or their biomass burned.

The study was led by Jingfeng Xiao, a research assistant professor at the Complex Systems Research Center, Institute for the Study of Earth, Oceans, and Space, at the University of New Hampshire.

Given that the climate would shift would probably cause a lot more droughts, the amount of sequestration is iffy given their own results.

The Quest for a Carbon Neutral Concrete

Many scientists currently think at least 5 percent of humanity's carbon footprint comes from the concrete industry, both from energy use and the carbon dioxide (CO2) byproduct from the production of cement, one of concrete's principal components.

Yet several studies have shown that small quantities of CO2 later reabsorb into concrete, even decades after it is emplaced, when elements of the material combine with CO2 to form calcite.

A study appearing in the June 2009 Journal of Environmental Engineering suggests that the re-absorption may extend to products beyond calcite, increasing the total CO2 removed from the atmosphere and lowering concrete's overall carbon footprint.

While preliminary, the research by civil and environmental engineering professor Liv Haselbach of Washington State University re-emphasizes findings first observed nearly half a century ago--that carbon-based chemical compounds may form in concrete in addition to the mineral calcite-now in the light of current efforts to stem global warming.

"Even though these chemical species may equate to only five percent of the CO2 byproduct from cement production, when summed globally they become significant," said Haselbach. "Concrete is the most-used building material in the world."

Researchers have known for decades that concrete absorbs CO2 to form calcite (calcium carbonate, CaCO3) during its lifetime, and even longer if the concrete is recycled into new construction--and because concrete is somewhat permeable, the effect extends beyond exposed surfaces.

It's decades away most likely, but it's an interesting idea all the same.

Plankton Blooms Don't Sequester Atmospheric Carbon

Oceanographers Jim Bishop and Todd Wood of the U.S. Department of Energy's Lawrence Berkeley National Laboratory have measured the fate of carbon particles originating in plankton blooms in the Southern Ocean, using data that deep-diving Carbon Explorer floats collected around the clock for well over a year. Their study reveals that most of the carbon from lush plankton blooms never reaches the deep ocean.

The surprising discovery deals a blow to the simplest version of the Iron Hypothesis, whose adherents believe global warming can be slowed or even reversed by fertilizing plankton with iron in regions that are iron-poor but rich in other nutrients like nitrogen, silicon, and phosphorus. The Southern Ocean is one of the most important such regions.

"Just adding iron to the ocean hasn't been demonstrated as a good plan for storing atmospheric carbon," says Bishop, a member of Berkeley Lab's Earth Sciences Division and a professor of Earth and planetary sciences at the University of California at Berkeley. "What counts is the carbon that reaches the deep sea, and a lot of the carbon tied up in plankton blooms appears not to sink very fast or very far."

The reasons, while complex, are most likely due to the seasonal feeding behavior of planktonic animal life, and specifically to the effects of the dark Antarctic winter on plant and animal growth and the mixing of surface and deep waters by winter storms. Phytoplankton blooms in the spring may indicate that much of the zooplankton (animal) population essential for carbon sedimentation has starved during the winter.

The Carbon Explorers involved in the study were launched in January, 2002, as part of the Southern Ocean Iron Experiment (SOFeX), a collaboration led by scientists from Moss Landing Marine Laboratory and the Monterey Bay Aquarium Research Institute. SOFeX was meant to test the Iron Hypothesis in waters between New Zealand and Antarctica during the Antarctic summer. The Berkeley Lab Carbon Explorers were originally intended to monitor the iron-fertilization experiment for 60 days, but they continued to report by satellite throughout the Antarctic fall and winter and on into the following year.

"We would never have made these surprising observations if the autonomous Carbon Explorer floats hadn't been recording data 24 hours a day, seven days a week, at depths down to 800 meters or more, for over a year after the experiment's original iron signature had disappeared," Bishop says.

He explains that "assumptions about the biological pump – the way ocean life circulates carbon – are mostly based on averaging measurements that have been made from ships, at intervals widely separated in time. Cost, not to mention the environment, would have made continuous ship-based observations impossible in this case. Luckily one Carbon Explorer float costs only about as much as a single day of ship time."

Bishop and Wood report their results in a forthcoming issue of the journal Global Biogeochemical Cycles. Preprints are now available to subscribers at http://www.agu.org/journals/gb/papersinpress.shtml.

Woooo! Go Colabbies! That said, if this bares out, this means any plan on using iron seeding is dead in the water.

Climate Engineering Is Now On The Table

The president's new science adviser said Wednesday that global warming is so dire, the Obama administration is discussing radical technologies to cool Earth's air. John Holdren told The Associated Press in his first interview since being confirmed last month that the idea of geoengineering the climate is being discussed.

One such extreme option includes shooting pollution particles into the upper atmosphere to reflect the sun's rays. Holdren said such an experimental measure would only be used as a last resort.

"It's got to be looked at," he said. "We don't have the luxury of taking any approach off the table."

Holdren outlined several "tipping points" involving global warming that could be fast approaching. Once such milestones are reached, such as complete loss of summer sea ice in the Arctic, it increases chances of "really intolerable consequences," he said.

Twice in a half-hour interview, Holdren compared global warming to being "in a car with bad brakes driving toward a cliff in the fog."

At first, Holdren characterized the potential need to technologically tinker with the climate as just his personal view. However, he went on to say he has raised it in administration discussions.

This was predicted almost 8 years ago by a climate scientist from here then. Even if we went cold turkey CO2wise, we'd still have the resultant climate since it'd take thousands of years for the CO2 to be sequestered naturally. If this is taken seriously, then we may end up with climate a couple degrees higher.It will take a lot of work to flush that much CO2 out. if we don't move fast enough, it'll end up being 5C more. Betcha.