Time to Double CO2 Levels: 234 Years at Current Rate

Plotting the NOAA ESRL Global Annual  Mean CO2 mole fraction increase (PPM) Data shows a relatively flat trend in the annual increase of CO2 in the atmosphere, with the mean from 1980-2009 (thru 9/09) of 1.65 Parts Per Million (PPM). At this rate, the time required to double CO2 levels from the current 386 PPM to 772 PPM is 234 years. The IPCC and alarmists assume CO2 levels are increasing exponentially, predicting CO2 levels will double as soon as 2050, but that is not what the data over the past 30 years show:

Note the spikes corresponding to El Nino years in 1983, 1987, 1995, (very strong) 1998, 2002,  and 2006.
The IPCC AR4 guesstimates of temperature change due to a doubling of CO2 greenhouse gases ("climate sensitivity") range from 2-4.5 degrees. Other authors estimate much less sensitivity of temperature due to a doubling of CO2 levels, some close to zero statistical significance, as noted in the graph below of temperature sensitivity to doubling of CO2 as a function of reference period:

also see the August 2009 paper by Lindzen and Choi which uses satellite data to determine climate sensitivity at 0.5 degrees due to a doubling of CO2 (that's 6 times less than the IPCC best estimate of 3 degrees). And see here. 

References:

Shaviv, N.J., 2005. On climate response to changes in the cosmic ray flux and radiative budget. J. Geophys. Res. 110, A08105. see On Climate Sensitivity and why it is probably small


Douglass, David H, B. David Clader, and R.S. Knox , 2004, Climate sensitivity of Earth to solar irradiance: update. Physics, abstract physics/0411002. http://citebase.eprints.org/cgi-bin/citations?id=oai:arXiv.org:physics/0411002

Stephen E. Schwartz, 2007, Heat capacity, time constant, and sensitivity of Earth's climate system, J. Geophys. Res., 112, D24S05, doi:10.1029/2007JD008746

Chylek P., U. Lohmann, M. Dubey, M. Mishchenko, R. Kahn, and A. Ohmura, 2007: Limits on climate sensitivity derived from recent satellite and surface observations. J. Geophys. Res., 112, D24S04, doi:10.1029/2007JD008740.

Petr Chylek & Ulrike Lohmann, 2008, Aerosol radiative forcing and climate sensitivity deduced from the Last Glacial Maximum to Holocene transition, Geophysical Research Letters, VOL. 35, L04804, doi:10.1029/2007GL032759