Global warming comes with unwanted implications but it has been going on for three decades that it is already changing people's perception of a normal climate. Most people, for instance, were not yet even born when the Earth had cooler than average climate.
Francois Pelletier, from the Population Division of the United Nations, said that the global median age is 29.4 years old which means that at least half of the world's population did not yet exist in February 1985, which the U.S. National Oceanic and Atmospheric Administration, or NOAA, the federal agency within the Department of Commerce that provides information on global temperatures, said was the last time that the Earth's temperature was below the average temperature of the 20th century.
"Because the last three decades have seen such a significant rise in global and regional temperatures, most people under the age of 30 have not lived in a world without global warming," said U.N.'s World Meteorological Organization (WMO) Secretary-General Michel Jarraud.
Because the warmer climate has become the norm, Peter Thorne, from the Nansen Environmental and Remote Sensing Center in Norway, said that historical records of the average temperature that have varied uses such as in determining how much insulation is needed for new buildings and in planning for crops, could no longer be a reliable guide in the future.
A WMO commission, which wanted for normal weather updates to be rolled out every decade, said that the concept of normal weather needs to be updated more frequently so as to have a better account of the warming climate.
Scientists, however, have noted that the increase in global temperature has slowed down in the last 15 years in what is dubbed as the "Global Warming Hiatus". As to why global warming appears to be taking a break, NASA atmospheric scientist Norman Loeb said that there are actually several opinions about it.
"Opinions vary about the hiatus, as some view it as evidence that man-made global warming is a myth," Loeb said. "Others explain that it is simply due to climate variability that is temporarily masking a longer-term temperature trend."
Loeb said that the hiatus likely has something to do with changes in solar radiation as well as aerosol particles and water vapor in the air. He also said that an El Nino-like climate variability pattern that coincided with the decelerating warming of global temperatures may also be a major factor.
