The photo shows Global warming trend about average temperature increase. Compared to the average temperature from 1961 to 1990, The average temperature in 1850 reduced 0.4°C. However, the average temperature in 2005 increased 0.4°C.
In 1750, the CO2 concentration in the atmosphere was 280ppm.
In 1955, the CO2 concentration in the atmosphere was 315ppm.
In 2004, the CO2 concentration in the atmosphere was 378ppm.