There is very little precise data when it comes to climate change. Are the Ice Caps growing or are they diminishing? Accurate measurements are hard to obtain. The International Earth Rotation and Reference Systems Service (IERS) provides very precise data that can answer this question. The IERS calculates leap seconds. Just like leap years add days to keep our calendar in sync with the actual amount of time it takes for the Earth to orbit the Sun, leap seconds are used to keep highly accurate atomic clocks in sync with clocks based on the Earth’s rotation. The Earth’s rotation has slowed down. To keep the clocks in sync leap seconds will have to be added at a constant rate. If the Earth’s rotation continues to slow down leap seconds will need to be added at an increasing rate.

The IERS determines the rotation of the Earth. Data only exists from 1972 to the present. From 1972 thru 1998 (26 years) 21 leap seconds were added. From 1999 to the present (9 years) only 1 leap second has been added. This means since 1999 to the present the Earth’s rate of rotation has increased. There are two possible (but not mutually exclusive) causes for this.

1. Some of the Earth’s mass has moved closer to the Earth’s axis of rotation similar to a spinning skater bringing his arms closer to his sides, and thus spinning faster. For the Earth this would occur when some of its ocean water is moved to the polar ice caps to form snow and ice. Satellite data shows the Earth’s atmosphere has been cooling since 1998.  This would cause a build up of snow and ice at the polar ice caps and thus increase the Earth’s rate of rotation. The time lines for the increase in the Earth’s rotation and the atmosphere’s cooling match. The Ice Caps are growing.

Mass could also have been moved closer to Earth’s axis of rotation by geological methods, but these would require more time. Read more here.

David Ameling has a BA in physics from UCLA. He had a career in computer software with large-scale real-time scientific systems including work with with military satellites. He has always been interested in climate.