This document discusses the history of climate change from the 19th century to present day. It notes that scientists have been observing rising global temperatures and their effects since the late 19th century, and their findings show that climate change poses risks to natural and human systems. Recent climate change is due primarily to human activities like burning fossil fuels that increase heat-trapping greenhouse gases in the atmosphere. If emissions continue at a high rate, average global temperatures could increase by over 3°C by 2100 with significant consequences.