The cleanest air in the world is at Tasmania's Kennaook Cape Grim. It's helping solve a climate puzzle
Living in smog filled cities can feel stifling. But there's a place in Australia where the air is so clean - it's considered among the purest in the world. On the far northwestern tip of Tasmania sits Kennaook Cape Grim. Winds blowing in from the wild southwest brings air that's free from pollution. So, scientists use the site to monitor the planet's baseline atmosphere, and they're now embarking on a new project to unlock a mystery in the Southern Ocean that could further help in understanding the impact of climate change.
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00:00It's a place that feels like the edge of the world, where a wild and rugged coastline
00:10is frequently lashed by winds, carrying some of the purest air on the planet.
00:15The air, I don't know if it's just me, but it's so crisp and clean.
00:23You feel like you can breathe it properly, it's magnificent.
00:29While locals love the north-west tip of Tasmania, scientists are also making the most of its
00:34unique location.
00:37When the wind blows in from the sea, it's travelled across the southern ocean from as
00:41far away as Antarctica, meaning it's avoided the contaminants like dust from landmasses
00:49and the dirty pollution of cities.
00:52The air here under baseline conditions is very, very clean, so it's a thousand times
00:56cleaner in terms of the number of particles than you would measure in Melbourne, for example.
01:01And that's Melbourne on a good day.
01:03The Kenil-Cape Grim Air Monitoring Station was set up almost 50 years ago.
01:09Its measurements are considered to be an accurate baseline of the global atmosphere because
01:14it's free from that local contamination.
01:18In a nutshell, we measure our greenhouse gases and ozone-depleting substances.
01:23We also measure the aerosols and reactive gases.
01:27Through a series of instruments, air gets channelled into a laboratory, where high-tech
01:32gadgets analyse the physical and chemical properties of the incoming flow.
01:38Six times a year, liquid nitrogen is used to chill high-pressure tanks that suck in
01:43thousands of litres of baseline air, adding to an archive that now dates back almost five decades.
01:51And what it's enabled us to do is, by filling multiple cylinders per year over many years,
01:57that we can go back and actually analyse old air when we get new instrumental techniques.
02:02The air archive reflects the human impact on the planet's rapidly changing atmosphere,
02:08which has seen a 25 per cent rise in carbon dioxide since the first tank was filled in
02:14the late 1970s.
02:16And while scientists have a clear picture of the past, the computations used to forecast
02:22future changes are lacking critical data.
02:28Almost all of that uncertainty in climate models has to do with our ability to, or our
02:34lack of ability to represent clouds very, very well.
02:38Australian and US researchers have now teamed up here at Kenauk-Cape Grim as part of an
02:44international mission designed to unravel some of the mysteries of clouds in the Southern Ocean.
02:50When clouds form in freezing conditions, tiny particles like dust and pollution can trigger
02:56ice crystals to develop.
02:58But because the air is cleaner in the Southern Ocean, the water droplets remain in a super-cool
03:04liquid state.
03:05These liquid clouds reflect more sunlight back into space, which means less heat is
03:11absorbed by the ocean.
03:13This phenomenon isn't accurately accounted for in current climate models.
03:18So we have a lot of instruments, radars and lidars and cameras that are constantly scanning
03:24these clouds to tell us what kind they are, how high they are, what they're made of, do
03:30they have ice, are they super-cooled liquid.
03:33The cloud project is set to run for the next 18 months, providing critical information
03:38that scientists hope can better prepare us for the changing climate.
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