Scientists have calculated that injecting 8 to 16 million tonnes of sulfur dioxide into the stratosphere each year, similar to the output of the eruption of Mount Pinatubo, could cool the Earth's temperature by 1 degree Celsius. Simulations over Antarctica show that this method, known as stratospheric aerosol injection, could lower global temperatures by 0.5 degrees Celsius over 20 years. However, there would be a trade-off as this method would also reduce the ozone layer to its 1990 levels, which is only a third of its pre-human impact state.