Arctic sea ice melting at unprecedented rate - meanwhile temperatures continue to rise in the Shire

Dr Sarah Perkins-Kirkpatrick explains how the Shire's September climate is changing. Plus, a closer look at declining Arctic sea ice.

BUREAU of Meteorology data shows September temperatures are rising in the Shire.

A typical September day is more than two degrees warmer than 50 years ago.

Similar increases have been observed around the world, but none as extreme as in the Arctic Circle, which is warming twice as fast as the global average.

The Arctic, where temperatures have previously been recorded as low as -70C, contains an expanse of sea ice.

In fact, estimates from September 2020 suggest it covers almost four million square kilometers.

However, rising temperatures mean Arctic sea ice is facing a rapid decline.

According to the Intergovernmental Panel on Climate Change , Arctic sea ice has decreased by around 40 per cent in the past 40 years due to climate change.

It is expected the Arctic will likely be sea ice free in September at least once before 2050.

Why melting matters:

The Arctic may be on the other side of the world, but declining sea ice has global implications.

Ice plays an important role in reflecting incoming solar radiation.

Indeed, 80 percent of the sunlight that strikes the ice is reflected back into space, helping to moderate temperatures around the world.

However, when ice melts, it exposes the darker ocean surface.

Rather than reflecting sunlight, the ocean absorbs it.

This begins a cycle of amplified heating and melting.

Warmer water delays ice formation during winter, and hastens melting over summer.

This is what is known as a positive feedback loop, which accelerates climate change.

These changes in the Arctic may, in turn, contribute to a further increase of temperatures across the globe, including in the Shire.

Fortunately, climate models show we still have time to curb the impacts of climate change by dramatically reducing our emissions - but we must act fast.

Want more information on how your climate is changing? Check out the last article in this series.

Dr Sarah Perkins-Kirkpatrick is a climate scientist at the University of New South Wales.

This column is part of a collaboration between Monash University and News Corp to deliver hyperlocal weather and climate information.