Hmmm.
CO2 isn't like cigarette butts pollution. It sticks around and has long term effects with long lags.
If nothing is done, the atmospheric CO2 level is predicted to reach 500-550 ppm in 2050 (40 years, not 200 years). But it won't stop there, it'll rise to 700-900 ppm by 2100 - http://www.climatesc...-1a-final-ch4.pdf (p.8 of the 52 page .pdf)
As the previous link pointed out, to stop the atmospheric CO2 level from rising, significant cuts in emissions are required. In addition, the temperature keeps rising long after the CO2 level stops rising - http://www.pnas.org/...12721106.abstract
This paper shows that the climate change that takes place due to increases in carbon dioxide concentration is largely irreversible for 1,000 years after emissions stop. Following cessation of emissions, removal of atmospheric carbon dioxide decreases radiative forcing, but is largely compensated by slower loss of heat to the ocean, so that atmospheric temperatures do not drop significantly for at least 1,000 years. Among illustrative irreversible impacts that should be expected if atmospheric carbon dioxide concentrations increase from current levels near 385 parts per million by volume (ppmv) to a peak of 450Â600 ppmv over the coming century are irreversible dry-season rainfall reductions in several regions comparable to those of the Âdust bowl era and inexorable sea level rise. Thermal expansion of the warming ocean provides a conservative lower limit to irreversible global average sea level rise of at least 0.4Â1.0 m if 21st century CO2 concentrations exceed 600 ppmv and 0.6Â1.9 m for peak CO2 concentrations exceeding ≈1,000 ppmv. Additional contributions from glaciers and ice sheet contributions to future sea level rise are uncertain but may equal or exceed several meters over the next millennium or longer.
The message isn't "it's hopeless, so why bother", but rather "it's an important problem that we need to start to seriously address sooner rather than later."
Nuclear power isn't a solution to transportation, where most of the oil goes (it's the 2nd largest source of the US's CO2 emissions and only slightly less than coal burnt for electricity - http://www.epa.gov/c...ns/co2_human.html )...
HTH.
Cheers,
Scott.
