Climate scientist Chip Knappenberger takes as his baseline the IPCC’s assumptions about temperature change due to Global Warming under a “Business As Usual” (BAU) scenario. For the sake of argument, he gives these numbers the benefit of the doubt, despite many questions about their accuracy.
From there, his calculations lead him to question whether a massive, economy-killing Global Warming bill like that proposed by Sens. John Kerry, D-Mass., and Joe Lieberman, ID-Conn., will even do anything to save the planet:
The global temperature “savings” of the Kerry-Lieberman bill is astoundingly small—0.043°C (0.077°F) by 2050 and 0.111°C (0.200°F) by 2100. In other words, by century’s end, reducing U.S. greenhouse gas emissions by 83% will only result in global temperatures being one-fifth of one degree Fahrenheit less than they would otherwise be. That is a scientifically meaningless reduction….
[T]he impacts on future sea level rise projections are equally insignificant. Instead of a projected sea level rise of 15.1cm by 2050, the Kerry-Lieberman bill produces a rise of 14.9cm. By 2100, the BAU projected rise is 37.1cm and the Kerry-Lieberman rise is 36.0cm. A century’s end sea level rise savings of 1.1cm, or 0.43 inches. Too small to be of consequence.
I recommend you read the whole post, which includes helpful graphs.