Abstract

In the recent two centuries, the Earth’s climate has been warming. By 2020, the Earth’s mean temperature anomaly ((TA), relative to the 1850-1900 mean Earth temperature) increased by nearly 1.1oC, leading to never before experienced environmental, economic and social events. The warm climate has triggered many extreme droughts, followed by hunger in Africa, withering heat in South Asia, multi-year forest fires in North America, devastating hurricanes in Central America and other unusual events. World scientists and society are indicating that the main cause of the Earth’s climate warming is an increase in anthropogenic greenhouse gases, specifically human-produced CO₂, which intercepts infrared (IR) solar radiation from the Earth’s surface and re-emits the IR back, warming land surface and air. Meanwhile, climate modeling has recently showed that CO₂ contribution to Earth’s climate warming is much less than 30%. Assuming that CO₂ contributes 25% to global TA increase and considering that by 2020, the Earth’ climate temperature anomaly increased by nearly 1.1oC, this paper is estimating that CO₂ has increased global temperature by 2020 to 0.28oC. Further, this investigation has shown that the rest 0.82oC (from 1.1oC) climate warming has been contributed by the interglacial climate period from the multi-year Milankovitch precession cycle.