Due date: _______________ Name ______________________________ Soil and Global Warming For this homework, you will read the three articles below, and answer the questions. You may copy your answers, as long a you use quotation marks around copied sections. The ﬁrst two articles are about how global warming might hurt soils, and cause even more global warming. The third (and last) article is about how soils might ﬁght global warming! Global Warming Is Changing Organic Matter In Soil: Atmosphere Could Change As A Result ScienceDaily (Nov. 28, 2008) — New research shows that we should be looking to the ground, not the sky, to see where climate change could have its most perilous impact on life on Earth. up this process which will increase the amount of CO2 that is transferred to the atmosphere. Scientists at the University of Toronto Scarborough have published research findings in the journal Nature Geoscience that show global warming actually changes the molecular structure of organic matter in soil. Until Simpson’s research, scientists didn’t know much about soil’s molecular composition. Part of the reason is that, from a chemical perspective, soil is difficult to analyze due to its many components, including bacteria, fungi and an array of fresh, partially degraded, or old plant material. Simpson’s team, which includes research collaborators Professors Dudley Williams and Andre Simpson, is uniquely positioned to address this new frontier. The team uses a NMR (Nuclear Magnetic Resonance) facility — the only NMR facility in Canada specifically dedicated to environmental research — to gain a detailed view of soil’s molecular structure and reactivity. “Soil contains more than twice the amount of carbon [in the form of organic compounds] than does the atmosphere, yet, until now, scientists haven’t examined this significant carbon pool closely,” says Myrna J. Simpson, principal investigator and Associate Professor of Environmental Chemistry at UTSC. “Through our research, we’ve sought to determine what soils are made up of at the molecular level and whether this composition will change in a warmer world.” Soil organic matter is what makes dirt fertile and able to support plant life — both of which are especially important for agriculture. Organic matter retains water in the soil and prevents erosion. Natural processes of decomposition of soil organic matter provide plants and microbes with the energy source and water they need to grow, and carbon dioxide is released into the atmosphere as a by-product of this process. Warming temperatures are expected to speed “From the perspective of agriculture, we can’t afford to lose carbon from the soil because it will change soil fertility and enhance erosion” says Simpson. “Alternatively, consider all the carbon locked up in permafrost in the Arctic. We also need to understand what will happen to the stored carbon when microbes become more active under warmer temperatures.” In their current study, Simpson’s team used an outdoor field experiment in the valley behind the UTSC campus to ensure natural ecosystem processes were preserved. Electrodes warmed the test soil between three and six degrees through winter and summer seasons, over a 14month period. Throughout the test period, the team analyzed the molecular composition of soil samples. 1. Soil contains more than __________ the amount of carbon than does the atmosphere. 2. Soil ____________________ is what makes dirt fertile and able to support plant life. 3. Warming temperatures are expected to _______________ the process of soil carbon turning into carbon dioxide, which will increase the amount of CO2 that is transferred to the atmosphere. 4. Losing carbon from the soil will _______________ erosion. 5. Soil is difficult to analyze because: Due date: _______________ Loss of soil carbon ‘will speed global warming’ Tim Radford, science editor, The Guardian, Thursday 8 September 2005 England’s soils have been losing carbon at the rate of four million tonnes a year for the past 25 years — losses which will accelerate global warming and which have already offset all the cuts in Britain’s industrial carbon emissions between 1990 and 2002, scientists warn today. The research dashes hopes that more carbon dioxide emissions might mean more vegetation growth and therefore more carbon removed from the atmosphere. The unexpected loss of carbon from the soils — consistently, everywhere in England and Wales and therefore probably everywhere in the temperate world — means more carbon dioxide in the atmosphere, which means even more global warming, and yet more carbon lost from the soil. “All the consequences of global warming will occur more rapidly. That’s the scary thing: the amount of time we have got to do something about it is smaller than we thought,” Guy Kirk, of Cranfield University, told the British Association Festival of Science, in Dublin. He and colleagues sampled the top 15cm (6in) of soil at almost 6,000 fixed points in England and Wales between 1978 and 2003, to measure the changes in living and decaying matter locked in pastures, croplands, forests, bogs, scrubland and heaths. Their findings, published in Nature today, show that carbon was being lost from the soil at an average of 0.6% a year: the richer the soils, the higher the rate of loss. When the figures were extrapolated to include all of the UK, the annual loss was 13m tonnes. Name ______________________________ There was no single factor other than global warming that could explain such changes in non-agricultural soils, they said. “These losses completely offset the past technological achievements in reducing carbon dioxide emissions, putting the UK’s success in reducing greenhouse gas emissions in a different light,” said Detlef Schulze and Annette Freibauer, of the Max Planck Institute, in Nature. In the past 25 years the average temperature has increased by half a degree centigrade and the growing season of the northern hemisphere has been extended by almost 11 days. Warmer soils will have encouraged greater microbial activity so more rapid decay of organic matter in the soil, leading to greater discharges of gases. For more than two decades, climate scientists have tried to calculate the planet’s annual carbon flow. Some of the carbon is absorbed by the oceans, to be trapped as limestone; some is locked in soil as peat or stored in woodland. The latest research implies that in a warmer world much of this “lost” carbon will find its way back into the atmosphere more quickly. The study confirms the value of long-term research: the national soil inventory was established in 1978 as a network of fixed points at intervals of three miles, and the scientists used went on using the same techniques to measure the changes in soil carbon over more than 20 years. Three-quarters of the planet’s soil carbon is trapped in the temperate zones, they note. Professor Kirk said: “It had been reckoned that the CO2 fertilization effect was somehow offsetting about 25% of the direct human induced carbon dioxide emissions. It was reckoned that the soil temperature emission effect would catch up in maybe 10 to 50 years’ time. We are showing that it seems to be happening rather faster than that.” 6. England’s soils have been losing carbon at the rate of __________ tons a year for the past 25 years. (Note: In England, they spell “tons” as “tonnes”.) 7. Why worry about soils losing carbon? (This answer will be different from your answers to #s 1–3.) 8. Does this research apply only to England, or could it apply to everywhere in the temperate parts of the world? 9. In the past 25 years the average temperature has increased by __________ centigrade and the growing season of the northern hemisphere has been extended by almost __________ days. 10.Why do warmer soils lose carbon faster than cooler soils? Due date: _______________ Name ______________________________ Science Update — Soil & Global Warming Making Sense of the Research Introduction You’ve probably heard of the greenhouse effect, which is the trapping of heat by certain gases in the earth’s atmosphere. And you’ve probably heard about these gases coming from cars, factories, and other man-made machines. But farming? One of the biggest environmental worries is global warming, which is caused by greenhouse gases like carbon dioxide. In this Science Update, you’ll hear how dirt might help fight it. Podcast transcript Putting greenhouse gases in the ground. I’m Bob Hirshon and this is Science Update. The burning of fossil fuels releases carbon dioxide into the atmosphere, the chef cause of the greenhouse effect. But for centuries, agriculture was the culprit. That’s because tilling and plowing expose more soil to the air, causing the carbon there to react and escape as carbon dioxide gas. Modern farming techniques slowly began to reverse this process. But senior scientist Jim Amonette of the Pacific Northwest National Laboratory wants to speed it up—to help fight global warming. Amonette: What we were trying to do is just figure out what the slight small thing a farmer or agricultural manager could do to increase the amount of carbon retained by their soil. His team found that making the soil less acidic, changing irrigation patterns, and promoting the formation of certain minerals can make a big difference. Amonette says that some soils could potentially double their carbon content to as much as five percent by weight. Amonette: So that means that an acre of soil six inches deep could contain 100,00 pounds of carbon. So a lot of carbon could be stored in an acre of topsoil. It’s hoped that these techniques could help put greenhouse gases safely under our feet. I’m Bob Hirshon for AAAS, the Science Society. As Amonette says, until recently, that’s where most of the human-made greenhouse effect came from. Remember that when industrial farming really took off, about two centuries ago, the earth’s soil contained about as much carbon as it could possibly hold. Now that much of that carbon has been released, there’s plenty of room to soak it back up. Unfortunately, cars, factories, and other human technologies are now pumping greenhouse gases into the atmosphere much faster than farming ever did. That’s why Amonette and his colleagues are trying to help the soil soak up more carbon faster. In other words, they’re using soil as a sink for carbon, to balance out the carbon from sources like cars and factories. Amonette’s goal was to speed up the activity of tyrosinase, an enzyme found in soils that’s critical to carbon absorption. He says treating fields with commercially produced tyrosinase would be expensive and impractical. So instead, he tinkered with natural variations in soil care to see which conditions made tyrosinase work most efficiently. The experiment involved trapping soil in 72 separate tubes. Each tube contained a soil sample that was exposed to slightly different conditions. Amonette found that soil acidity, the use of common additives, and irrigation patterns all could influence the efficiency of the soil’s carbon uptake. And these are changes that farmers could make fairly easily at low cost. Next, he plans to test his theories in the field, by treating large patches of soil in different ways. If his predictions from the lab hold up, they’ll be able to make recommendations to farmers. 11.How can soils help remove carbon from the atmosphere? 12.If humans had never invented farming, but still created the same level of air pollution we have today, would the soil be more, less, or equally able to remove carbon from the atmosphere? Explain. 13.What is tyrosinase? What role does it play in the research described on this web page? 14.If these findings hold up, what do you think it would t
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