The study of climatic history revealed the last four years 2015 to 2018 were the hottest in the past 2,000 years. According to Prof. Philip Jones, director of the climatic research unit in the University of East Anglia, no one can explain rapid warming of the earth in the late 20th century. Greenhouse gases in the atmosphere are responsible for climatic change. To confirm whether regarding the claims of climate. Prof. Jones and Prof Michael Mann climate expert at the University of Virginia started the study of the global climate over the past 2,000 years. The measurements or sources of the earth’s temperature does not exist for such a long period. The scientists had to find other indicators to which can provide information related to the temperature of earth before 2 millennia.
Corals, tree rings, ice cores, lake, and ocean sediments cores provide information regarding past conditions. This type of data is known as proxy data and can be used together to tell about the earth’s climate in the past. The scientists to know the climate history looked at tree trunks that keep record of the local climate. The rings of the tree trunk spreading out from the center grow to different thicknesses as per the climate. Scientists observed at sections of the tree that lived for hundreds of years. Moreover, the scientists studied cores of ice drilled from Antarctica and Greenland. Sometimes over hundreds of years as ice forms, it traps air that holds clues of local climate at that time. As per Professor Jones, there is no evidence that climate before 2000 years is warmer then it is now. He added, from 1980 onwards is the warmest period of the last two millennia.
According to Geophysical Research Letters, the temperature of the earth fluctuated slightly, becoming warmer or cooler by 0.2C. The temperature of the earth has increased by at least that amount every century. According to scientist’s carbon dioxide is driving climate change. As per Dr. Sallie Baliunas an Observatory at the Harvard College, the earth went through a cycle of climatic change during the 20th century. From 1900 to 1940 the planet warmed slightly and cooled from 1940 to 1970, from 1970 onwards the plant warmed up again. More than 80% of the carbon dioxide had been produced post-1940. According to her, if carbon dioxide was the reason behind global warming the temperature of the planet would increase but not decrease.