evidence: A University of Arizona-led effort to reconstruct Earth's climate since the last ice age, about 24,000 years ago, highlights the main drivers of climate change and how far out of bounds human activity has pushed the climate system. [...] - It verified that the main drivers of climate change since the last ice age are rising greenhouse gas concentrations and the retreat of the ice sheets. [...] An online search of "global temperature change since the last ice age" would produce a graph of global temperature change over time that was created eight years ago.