Page 376 - Geosystems An Introduction to Physical Geography 4th Canadian Edition

THEhumanDENOMINATOR 11 Taking Action on Climate Change
CLIMATE CHANGE HUMANS
• Climate change affects all Earth systems.
• Climate change drives weather and extreme events, such as drought, heat waves, storm surge, and sea-level encroachment, which cause human hardship and fatalities.
HUMANS CLIMATE CHANGE
• Anthropogenic activities produce greenhouse gases that alter Earth’s radiation balance and drive climate change.
11a Conventional CO2
Less soil CO2 retention Less More
No-Till CO2
More soil CO2 retention
More carbon is retained in soils with the practice of no-till agriculture, in which farmers do not plough fields after a harvest but instead leave crop residue on the fields. (See discussion in Chapter 18.) In the photo, a farmer
uses no-till agricultural practices in New York by planting corn into a cover crop of barley. [After U.S. Department of Energy Pacific Northwest National Laboratory. Photo by NRCS.]
11b
Parade participants in different costumes march during the Global Day of Action Against Climate Change on December 8, 2007, in suburban Quezon City, north of Manila, Philippines. [Pat Roque/AP Photo.]
11d
Through the International Small Group and Tree Planting Program (TIST), subsistence farmers have been planting trees to reverse deforestation and combat climate change. Farmers earn greenhouse gas credits for each tree planted based on growth and the amount of carbon stored; these credits translate into small cash stipends. Scientists think that planting trees is one of the simplest and most effective ways to combat climate change.
[Charles Sturge/Alamy.]
ISSUES FOR THE 21ST CENTURY
11c
Climate-awareness advocates holding umbrellas form the number “350” on the steps of the Sydney Opera House in downtown Sydney, Australia, in 2009. The “350” signifies the concentration (in ppm) of atmospheric carbon dioxide that scientists have determined to be sustainable for Earth’s climate system. [David Hill/Getty
Images.]
How will human society curb greenhouse gas emissions and mitigate change effects? Some examples:
• Using agricultural practices that help soils retain carbon.
• Planting trees to help sequester carbon in terrestrial ecosystems.
• Supporting renewable energy, and changing lifestyles to use fewer resources. • Protecting and restoring natural ecosystems that are carbon reservoirs.
geosystemsconnection
Chapter 11 presents a synthesis of climate change evidence and its human causes, ending Part II and the focus on Earth’s atmosphere. Next we move to Part III, Chapters 12 through 17, “The Earth–Atmosphere Interface”—where systems meet at the lithosphere. We begin with the en- dogenic system in Chapters 12 and 13, describing how energy wells up within Earth with enough power to drag and push portions of Earth’s crust as continents migrate. We also study rock- forming processes and the nature of crustal deformation, as well as the dramatic events of earth- quakes and volcanic eruptions.
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