A study undertaken by NASA has revealed that the impact of different factors on the climate differs across the world. The study stated that increase in the global temperatures in future must be studied by taking into account the impact of various natural and man-made factors on climate. The study reports that conclusions about the impact of various factors cannot be generalized across the countries.

Assess the modifications in the climate, the Transient Climate Response (TCR) and Equilibrium Climate Sensitivity (ECS) of Earth have to be calculated by the researchers. Both the parameters are estimated changes in global mean surface temperature as a result of atmospheric carbon dioxide increasing twofold, across various time periods. TCR is calculated over short term, while ECS is calculated for long term subsequent to climate system achieving equilibrium and temperatures stabilizing.

To calculate the above parameters, researchers simplified assumptions and did not include any other factors, apart from carbon dioxide, that affect climate, like aerosols. “The problem with that approach is that it falls way short of capturing the individual regional impacts of each of those variables,” said Climate Scientist Gavin Schmidt, the Director of Nasa's Goddard Institute for Space Studies (Giss) in New York and a co-author on the study.

Researchers have assessed the affect of various factors, like greenhouse gases, natural and manmade aerosols, ozone concentrations, and land use changes, on temperature through the data available for the period 1850-2005. The study revealed that each factor affected the temperature under a particular set of conditions.