Attribution of recent climate change is the effort to scientifically ascertain mechanisms responsible for relatively recent changes observed in the Earth's climate. The effort has focused on changes observed during the period of instrumental temperature record, when records are most reliable; particularly on the last 50 years, when human activity has grown fastest and observations of the upper atmosphere have become available. The dominant mechanisms to which recent climate change has been attributed all result from human activity. They are:

• Increasing atmospheric concentrations of greenhouse gases
  
• Global changes to land surface, such as deforestation
  
• Increasing atmospheric concentrations of aerosols

Greenhouse Gases • Global warming potential • Greenhouse effect • Carbon dioxide • Keeling Curve • Climate sensitivity • Solar variation • Radiative forcing • Global dimming • Global cooling • Urban heat island • Cloud forcing • Deforestation • Glaciation • Ocean variability • Plate tectonics • Orbital variations • Volcanism