An influx of pollution from Asia in the western United States and more frequent heat waves in the eastern U.S. are responsible for the persistence of smog in these regions
over the
past quarter century despite laws curtailing the
emission of smog - forming chemicals from tailpipes and factories.
Over the
past quarter century, G20 carbon dioxide
emissions had risen by almost 50 percent while per capita
emissions had gained by about 18 percent, reflecting population growth, it said.
You may wonder why the government finds the need to pursue such action since 1) U.S. carbon dioxide
emissions have already topped out and have generally been on the decline for the
past 7 - 8 years or so (from technological advances in natural gas extraction and a slow economy more so than from already - enacted government regulations and subsidies); 2) greenhouse gases from the rest of the world (primarily driven by China) have been sky - rocketing
over the same period, which lessens any impacts that our
emissions reduction have); and 3) even in their totality, U.S. carbon dioxide
emissions have a negligible influence on local / regional / global climate change (even a immediate and permanent cessation of all our carbon dioxide
emissions would likely result in a mitigation of global temperature rise of less than one -
quarter of a degree C by the end of the
century).