The World Meteorological Organisation (WMO) has issued its latest Greenhouse Gas Bulletin, with data gathered up to 2008. You can see the report HERE [.pdf]. It does not make comfortable reading.
A series of readings taken over more than 50 years at the Mauna Loa observatory in Hawaii shows the amount of carbon dioxide in the atmosphere rising relentlessly. The report observes: “The amount of CO2 in the atmosphere is increasing exponentially at a rate of about 0.5% per year”.
The amounts of carbon dioxide, methane and nitrous oxide in the atmosphere had reached new highs by 2008. Total radiative forcing by all long-lived greenhouse gases increased by 26.2% between 1990 and 2008, and by 1.3% between 2007 and 2008.
The bulletin goes into more detail on the growth rates of greenhouse gases, with figures on relative versus absolute increases. Note that in almost all cases, the levels of these gases are increasing.
The report is just four pages long, and I commend it to anyone who wishes to take an intelligent position on the subject.