Global Temperatures Forced by Solar Irradiation and Greenhouse Gases?

The emission of greenhouse gases has been definitively linked to global warming, although the increased level of greenhouse gases may have a nonlinear relationship to warming effects. Climate is also affected by changes in solar irradiation. This examination of these variables considers data from the Vostok ice core samples and Holocene data, and their relevance to increasing temperatures during the 1990s. These data suggest that changes in solar irradiation account for the major climate shifts, although these effects are mitigated by volcanic eruptions and greenhouse gases.