Page 121 - Geosystems An Introduction to Physical Geography 4th Canadian Edition

THEhumanDENOMINATOR 3 The Shared Global Atmosphere
ATMOSPHERE HUMANS
• Earth’s atmosphere protects humans by ltering harmful wavelengths of light, such as ultraviolet radiation.
• Natural pollution from wild res, volcanoes, and wind-blown dust are detrimental to human health.
New low emissions standards for diesel vehicles were implemented in London in 2012. Owners must comply or face a daily penalty fee. Stricter regulation is one strategy to control increasing air pollution from the transportation sector. [Daniel Berehulak/Getty Images.]
This 2012 portrait of global aerosols shows dust lifted from the surface in red, sea salt in blue, smoke from
from volcanoes and fossil fuel emissions in white. [NASA.]
3e
Researchers at the South Pole monitor ozone using a balloonsonde, carrying instruments to 32 km altitude. Significant seasonal ozone depletion still occurs, despite decreases in ozone-depleting chemicals. [NOAA.]
ISSUES FOR THE 21ST CENTURY
HUMANS ATMOSPHERE
• Depletion of the ozone layer continues as a result of human-made chemicals that break down ozone. Winds concentrate the pollutants over Antarctica, where the ozone hole is largest.
• Anthropogenic air pollution is concentrated over urban areas, which are home to half the world’s population. Unhealthy pollution levels are becoming more widespread in some areas, such as northern India and eastern China; other regions have improved air quality, as in the
3a
Los Angeles metropolitan area.
China burns more coal and emits 3b more CO2 than any country on
Earth. Air pollution is severe, with PM2.5 levels regularly reaching
harmful levels above cities. American companies are testing clean energy technologies here, with hopes of using them around the world. [Jo Miyake/Alamy.]
3d
400 380 360 340 320 300 280 260 240 220 200 180 160 140 120 100
80 60
3c
Clean burning cooking stoves will reduce the amount of fine particulates such as black carbon in developing countries. Several international initiatives are working toward this goal. [Per-Anders Pettersson/Getty Images.]
20 20
19
11 10
86–2009 average
Maximum
South Pole Total Ozone
and minimum
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
• Air quality will worsen in Asia unless human-made emissions are reduced. Air pollution will continue to improve in regions where emissions are regulated, such as in Europe, the United States, and Canada.
• Nitrogen emissions may worsen acid deposition worldwide unless regulatory action is taken.
• Alternative, clean energy sources are vital for reducing industrial pollution worldwide.
• Increases in fuel efficiency, vehicle-emissions regulations, and use of alternative and public transportation are critical to reduce urban pollution.
• Reductions to lower CO2 emissions and slow rates of climate change are needed mitigations.
geosystemsconnection
We traversed the atmosphere from the thermosphere to earth’s surface, examining its composition, temperature, and functions. electromagnetic energy cascades toward earth’s surface through the layers of the atmosphere where harmful wavelengths are filtered out. We also examined human im- pacts on the atmosphere, including the depletion of the ozone layer and air pollution, one example being acid deposition on the landscape.
in the next chapter, we focus on the flow of energy through the lower portions of the atmo- sphere as insolation makes its way to the surface. We establish the earth–atmosphere energy bal- ance and examine how surface energy budgets are powered by this arrival of energy. We also begin exploring the outputs of the energy–atmosphere system, looking at temperature concepts, tem- perature controls, and global temperature patterns.
Total column ozone (Dobson units)
85