Human evidence: Matching temperature trends

  • Image: NASA Goddard Space Flight Center

  • Data: IPCC

  • Data: IPCC

  • Data: IPCC

  • Data: IPCC

    Scientists have calculated that a combination of increased solar activity and decreased volcanic activity contributed to some of the global warming observed in the first half of the 20th century. But even a combination of all known natural factors can’t account for the warming of about 0.5 °C observed since 1970. However, when scientists included the effects of human activities in their calculations, they were able to account for the measured trend in global temperature within the uncertainties.