Scientists say the sun is expected to be unusually cool by 2050. Scientists have termed it as “grand minimum,” a particular low point.
Sun ejects more ultraviolet radiation and generates sunspots and flares, at its high points. As the sun’s surface goes calm, it ejects less ultraviolet radiation.
Physicist Dan Lubin at the University of California San Diego has calculated an estimate of how much dimmer the sun is likely to be when the next such grand minimum takes place.
His team’s study, “Ultraviolet Flux Decrease under a Grand Minimum from IUE Short-wavelength Observation of Solar Analogs,” has been published in the journal Astrophysical Journal Letters.
It finds that the sun is likely to be 7 percent cooler than its usual minimum. According to cooling spiral of recent solar cycles another grand minimum is likely to be just decades away.
One particularly cool period in the 17th century guided their research. Scientists say the sun is expected to be unusually cool at next “grand minimum” period.
After hundreds of thousands of years of CO2 levels not exceeding 300 parts per million in air, the concentration of the greenhouse gas is now over 400 parts per million, continuing a rise that began with the Industrial Revolution.
One simulation of a grand minimum on the Earth’s current climate anticipates a reduction of solar warming by 0.25 percent over a 50-year period between 2020 and 2070.
While the global average surface air temperature appears to cool by “several tenths of a degree Celsius” in the initial years, this reduction was rapidly overtaken by ever-increasing trends.
“A future grand solar minimum could slow down but not stop global warming,” the study finds.