Washington: The speed of global warming caused by humans for the past 150 years is faster than anything seen since the last ice age, around 24,000 years ago, according to a study.
The team led by researchers at the University of Arizona, US also verified that the main driver of climate change since the last ice age was the increase in the concentration of greenhouse gases and ice sheet retreats.
This research, which was published recently in the journal Nature, suggested general heating trends for the past 10,000 years, completing a decade long debate about whether this period patted warm or cooler in the paleoclimatology community.
The researchers found that the magnitude and level of heating for the past 150 years went far beyond the magnitude and the level of change for the past 24,000 years.
“This reconstruction shows that the current temperature has never been previously in 24,000 years, and also shows that global warming speed caused by humans is faster than anything we have seen at the same time,” said Jessica Tierney, a university professor at University of Arizona, and research authors.
“The fact that we today so far far from what limits we consider normal is the reason for alarms and must be surprising to everyone,” said the author of Timah Matthew Osman, a postdoctoral geoscience researcher at the University of Arizona.
The team creates a global temperature change map for each 200-year interval back 24,000 years.
The researchers combined two independent temperature data – temperature of sea sedimen and computer climate simulation – to create a more complete picture of the past.
They see the marine sediment chemical signature to get information about past temperatures.
Because the temperature changes from time to time can affect the chemical of the dead animal shell, Paleoklimatology can use the measurement to estimate the temperature in an area.
The researchers noted that this method was not a perfect thermometer, but it was the starting point.
The climate model is simulated a computer, on the other hand, providing temperature information based on the best understanding of scientists about climate system physics, which is also not perfect, they said.
The team combines both methods to utilize their respective strengths.
“To estimate the weather, meteorological experts start with models that reflect the current weather, then add observations such as temperature, pressure, moisture, wind direction, and so on to make an updated estimate,” Terney said.
The team applied this same idea to the past climate.
“With this method, we can take advantage of the relative benefits of each of these unique datasets to produce limited observation reconstruction, consistently dynamically, and spatially completed from the previous climate change,” Osman added.
The team is now working using a method to investigate climate change even further in the past.