Man-made Global Warming dates back 200 years

According to an Australian based research, the first signs of global warming had appeared as early as 1830, during the first Industrial Revolution itself. Our knowledge about earth's temperature history is very limited, as it is mostly based on temperature recording instruments, that came into use in the late 1880s. This situation prompts scientists, to explore natural archival sources to gauge temperatures that existed in the past. Researchers of this new study, have managed to collect 500 years of organic data found in tree rings, coral reefs and ice sheets, that had survived through ages. The researchers claim that, the greenhouse gas emissions from industries, left their first traces in the temperatures of tropical oceans and the Arctic around 1830. This challenges the widespread views, that man-made climate change began only in the 20th century.