NARRATION

Have you noticed anything odd round your place lately? A fish you've never caught before. Unusual events. Weird weather. Well, I've certainly noticed something odd round my home.

Dr Jonica Newby

I bought this place 12 years ago. And, in that whole time, it never flooded. Nor in the 20 years the old guy had it before me. In the last two years, it's flooded ten times.

NARRATION

I've pretty much stopped mopping. And, like many of us, as I survey the damage, I wonder if this is Climate Change, a rogue La Nina or just a really rainy year. Has the weather changed in the last 100 years or not? So, I'm heading on an investigation that's all about the simple facts. Real tidal gauges, actual temperature records. And this will be a proper weather report, going round Australia to the places you and I live and play. It's time to take the temperature of Australia. And, when it comes to weather, there's one organisation perfectly placed to guide me. They formed 100 years ago. They are the Bureau of Meteorology.

Dr Jonica Newby

Hello, Karl.

Dr Karl Braganza

How's it going, Jonica?

Dr Jonica Newby

Good. And... So you're going to run us through a national, 100-year Australia health check/weather report.

Dr Karl Braganza

That's right. Today we're going to do a national round-up of Australia's temperature, hydration and its circulation.

Dr Jonica Newby

Fantastic. So I reckon we start straightaway with temperature, which means I'm heading... here.

NARRATION

I don't want to start with the heat, but with the cold. Is it as cold as it used to be? And where better to view the cold than from our nation's frosty tips? Our enchanted, legendary snowy mountains... where I love to ski.

Dr Jonica Newby

You may think me elitist, but I prefer to think it's the genetic imperative of my Norwegian ancestry.

NARRATION

And those Nordic genes of mine have a keen interest in what's happened to the snow.

Dr Jonica Newby

Well, this is 1964, the biggest dump on record. You look at photos like this, and you think things must have changed. But have they really? Is it anecdotal or real? To find out, you have to go to the records.

NARRATION

We're off to Spencer's Creek, where the Snowy Hydro scheme has been taking snow-depth measures every week since 1954. Dr Ken Green has been monitoring the snow for decades.

Dr Kenneth Green

We've got 65 inches, which...

Dr Jonica Newby

Inches?!

Dr Kenneth Green

Yes, inches. It's been done since 1954. So they're not going to change their methods now.

Dr Jonica Newby

(Laughs)

Dr Kenneth Green

Which is about... 162cm.

NARRATION

Snow cover swings wildly from year to year. So the best way to see the signal in the record is to compress it into five-year average trends.

Dr Jonica Newby

So, how are we going to do the trend line?

Dr Kenneth Green

We'll put this in as the trend line.

NARRATION

Hmm. In 60 years, we've lost a third of our total snow cover. But there is some rough comfort for my skiing aspirations. And that is that the beginning of the season hasn't really changed.

Dr Jonica Newby

So, basically, since 1954, snow depth in July is much the same. When you reach September, it starts to drop off. So that by October it's noticeably less. Essentially, spring is coming earlier.

NARRATION

It's even clearer when you look at the records for the thaw, now two weeks earlier than in the '60s. And the snowline appears to have lately moved up from 1,500m to 1,600m.

Dr Kenneth Green

This actually used to be a ski run, coming down here across the road. And now you wouldn't even dream of it.

NARRATION

So what HAS happened to Australia's cold?

Dr Jonica Newby

Right. Our first national round-up. So we're looking at minimum temperatures. And, Karl, basically, this is how cold it gets at night.

Dr Karl Braganza

That's correct, Jonica. If we start at the Snowy here, we've warmed by about 1.1 degrees since a century ago. And that's similar to Perth, Sydney. If we're looking over here at Cairns, it's almost 2 degrees since 1910.

Dr Jonica Newby

Two degrees, so hot nights.

Dr Karl Braganza

Well, hotter nights than they used to have, yeah - on average.

NARRATION

And how do we know this to be true? Well, because, frankly, the data collection behind it is mind-boggling. This is the Victorian regional headquarters of the Bureau of Meteorology.

Dr Jonica Newby

So how many things are kind of feeding into all of this?

Kevin Parkyn

Um, too much, really for the brain to comprehend, to be honest. And that's why we have a lot of alerts that help us.

NARRATION

There are nearly 800 weather stations across Australia, with over 500 now fully automated. Of these, 112 sites have information that historically goes back far enough and is accurate enough to count as blue-chip and be used as part of the 100-year record.

Dr Jonica Newby

OK, so, to be in the top 100, you have to have a few things going for you. First of all - quality instruments. So this is a fully automated platinum temperature probe. Second, you have to have reliable records. So these platinum records go back to 2001. And then this old-fashioned but still accurate mercury goes back to 1910.

NARRATION

Third, the station has to be well away from urban heat islands, so not in a big city. All this data is then fed by cables to central stations at the national bureau headquarters in Melbourne, where it ends up here.

Dr Jonica Newby

I'm on the secret level of the bureau now. This is the lair of the weather supercomputers. They have their own full-time staff of 22 IT slaves on 24-hour call making sure nothing upsets them.

NARRATION

A gazillion cable feeds are swallowed here, digested and then spat over there.

Dr Jonica Newby

This temperature controlled block of pampered bits and bytes contains all the records. This, essentially, is the history of Australia's weather.

NARRATION

And this is how the bureau knows how much minimum temperatures have gone up in 100 years.

Dr Jonica Newby

So that's night-time minimums, but I bet what most of you are more interested in is what's happened to daytime maximums. And, for that... I'm heading here.

NARRATION

This is another one of my favourite spots in Australia - sassy, sexy, St Kilda, Melbourne.

Dr Jonica Newby

I lived here in my 20s, and, coming from Sydney and Perth, can I say Melbourne had a bit of a reputation for its weather?

NARRATION

So, when I moved here, I bought a coat, a scarf, gloves, and these, but what no-one told me was how darn hot it was going to get. And I'm not the only one shedding her coat early. Butterflies are really temperature-sensitive. Melbourne's common brown butterfly now emerges from its chrysalis nearly two weeks earlier than in 1940. So, how much hotter has Melbourne got?

Dr Jonica Newby

OK, Doctor, our national round-up of maximum temperatures. So what do we have?

Dr Karl Braganza

You can see here - Sydney through to Melbourne, Canberra, Hobart, they've warmed up by about 0.7 of a degree. And in some capitals a lot less. Adelaide - 0.3. But if you go over to the west - Perth - and into the centre - Alice Springs - you've got 1.1 to almost 2 degrees of warming.

Dr Jonica Newby

Wow.

NARRATION

In 100 years, the centre has heated up more than the coast.

Dr Jonica Newby

So, the further inland you are, in Australia, the more the maximum temperatures will have gone up?

Dr Karl Braganza

As a general trend, yeah.

NARRATION

Overall, averaging maximums and minimums, our nation's core temperature has gone up 0.9 of a degree. But, in 2009, Victoria's temperature spiked in a lethal fever.

Dr David Jones

In Melbourne we saw the previous February record broken by more than 3 degrees.

NARRATION

Melbourne hit 46.5 degrees. Hopetoun hit 48.8.

Dr David Jones

We broke the Victorian record by 1.6 degrees. You know, these are records going back over 50 years. You know, you're not breaking 'em by... by, you know, a few tenths of a degree - you're breaking 'em by whole degrees or more.

NARRATION

And you know what happened next. Of course, it became known as 'Black Saturday'. 173 people died in those fires, but they weren't the only casualties of this extreme heat event.

NARRATION

When health researchers went back over the mortality records, it turned out an extra 370 people died during that week than you'd expect.

Dr Jonica Newby

Essentially, it means that they were tipped over the edge by heat stress. There's a rather confronting in-house term that's used for this. They call it 'premature harvesting'.

NARRATION

And it isn't just humans feeling the heat. One day, on a country golf course way down south in WA, it started raining black cockatoos. It certainly surprised the locals, let alone the birds. The year was 2010, and the temperature hit 48 degrees. An entire flock of endangered Carnaby's cockatoos literally cooked where they roosted. And can you see what these are? Budgerigars. Budgerigars that fell from the sky during another WA heatwave in 2009.

Dr Jonica Newby

Alright, so this next diagnostic is... a measure of extremes.

Dr Karl Braganza

It is. And what we've seen is more and more stations are breaking extreme heat in the last 100 years, and less are breaking extreme cold.

NARRATION

In fact, in the last ten years, the number of stations breaking extreme heat records has doubled those breaking extreme cold.

Dr Karl Braganza

So, frosty nights are becoming less common, but extreme heat days are becoming more common.

NARRATION

Now, some of my friends like to joke that if things go really pear-shaped we can always move to Tassie. Well, one company already has. It's a company that makes something dear to many of our hearts - alcohol.

Dr Jonica Newby

I love the smell of baby wine growing in the morning.

NARRATION

Two years ago, a famously Victorian company bought up big here in Tasmania. And they did so specifically to future-proof themselves against temperature. They are the family dynasty Brown Brothers, though I seem to have found myself a Brown sister.

Dr Jonica Newby

So, had you actually noticed some damage to your bottom line, basically, due to temperatures?

Katherine Brown

Yeah. Um, we... Well, we put up with ten years of drought.

Dr Jonica Newby

Yeah.

Katherine Brown

Um, and also, um, one of our vineyards in Victoria where we grow our top-quality sparkling wines... We got the warmer weather earlier, and the bud bursts had already come through, so the frost came in and actually killed all the shoots. That wiped out a whole vintage.

NARRATION

The wine industry's detailed records show grapes in Australia's south are ripening, on average, 20 days earlier than in 1985.

Katherine Brown

Talking to our scientists, winemakers and viticulturists, um, they really pretty much turned to the board and said, 'We have to find this cooler-climate property because within decades we could see a 2-degrees temperature rise in our current vineyards in Victoria.' So, they pretty much told us that if we continued to want to do what we do best, make quality wine, we had to come south.

NARRATION

And now I'd like to demonstrate a little game of chance.

Dr Jonica Newby

So the chance of one month being above-average temperature, is one in two. The chance of the next month also being above-average temperature, is one in four. The chance of the next month also being above-average temperature, is one in eight.

NARRATION

So what do you think are the chances of having 330 months in a row of above-average temperatures? Because, since February 1985, we have had... 330 months in a row of above-average (global) temperatures.

Dr Mark Howden

It's really extraordinary. If it was just by random chance alone, then there's only a 1 in 100,000 chance that that would have happened in the absence of human influence.

Dr Jonica Newby

So, this bottle of red represents the chance that that run of temperature increase was caused by natural variability, sunspots or volcanoes.

Dr Mark Howden

That's right.

Dr Jonica Newby

Right!

Dr Jonica Newby

I think we should drink it.

Dr Jonica Newby

Cheers.

NARRATION

So that's temperature. Next up, I want to check on Australia's state of circulation. I mean that stuff we're girt by - the sea. I'm still in Tassie because something odd has been happening in these waters - strange sightings, mysterious beasties where never before seen.

Dr Jonica Newby

I'm talking fish. And where there's fish, there's a fishing story.

Mark Nikolai

It was about two years ago, and I can remember it vividly. I saw a small group of fish come towards us. I said to my son, 'Wheel in your rod as fast as you possibly can.' When suddenly - bang. It just took off. The reel itself was actually screaming. My son didn't know what to do. He said, 'Dad, Dad, what do I do, what do I do?' I said, 'Nothing, son. Just hang on to the reel and wait for the fish to slow down.' So that's what we did. It took us about 40 minutes, I suppose.

Dr Jonica Newby

40 minutes?!

Mark Nikolai

40 minutes because the fish weighed more than the line capacity.

NARRATION

Brand spanking new to Tasmania, it was a yellow-tailed kingfish.

Dr Jonica Newby

A real yellow-letter day.

Mark Nikolai

That's it.

NARRATION

It's exciting times for Tasmanian fishermen. With so many new fish arriving, they've teamed up with scientists to plot them. They've seen leather jacks, green turtles, dusky morwong...

Mark Nikolai

It's actually really good news for Tasmanian fishermen, 'cause all the New South Wales fish are moving south into our waters.

NARRATION

All in all, scientists have confirmed 45 new species have, like Brown Brothers, shipped on down to Tassie.

Dr Jonica Newby

Well, obviously, if fish from the big island are moving down, the water here must have got warmer.

NARRATION

How much warmer?

Dr Jonica Newby

It's not too bad. Ooh, yes it is!

Dr Jonica Newby

Alright, Dr Karl. National round-up time again. 100-year health check. Circulation.

Dr Karl Braganza

Sure. What we're going to look at now, Jonica, is the sea-surface temperatures around Australia. And what we've seen is about a degree of warming over the last century. But you can see over the East Coast we have more warming than we do over the West Coast. There's some hot spots as well. And that's off the coast of Victoria, Tasmania.

NARRATION

Sea temperatures here off Tasmania have risen an astounding 2.28 degrees. That's about four times the global ocean average.

Dr Karl Braganza

And we think that's got something to do with changes in the East Australian Current, but we're not exactly sure why.

NARRATION

And, last year, West Australia's blood began to boil. Time to visit my childhood home. I'm a Cottosloe girl, Which means I grew up not noticing how wide the verges are...

Dr Jonica Newby

You can fit a whole Sydney house on this verge!

NARRATION

..and dodging sharks on my local beach. And over there is Rottnest - Perth's playground.

Dr Jonica Newby

I think I've swum in just about every rock pool round here. And, look, the water was lovely and warm. But what I'm about to tell you shocks me. Last year, on 28th February, the water in here hit 26.4 degrees. 26.4 degrees?! That's ridiculous.

NARRATION

It killed the coral.

Dr Jonica Newby

And has that ever happened here at Rottnest?

Dr Damian Thompson

Not that we're aware of. Not in 40 metres of water.

NARRATION

In fact, it was part of the biggest heatwave to hit Australia's waters ever. It began just north of Ningaloo Reef, hitting it heartbreakingly with the force of a pot of boiling oil.

Dr Damian Thompson

In some places, up to 80% of what was there before is now no longer there.

Dr Jonica Newby

Really just gone. Dead. So that's it.

Dr Damian Thompson

Gone, dead, yeah. Covered in algae.

NARRATION

It travelled 1,200km south, reaching all the way to the southernmost tip of WA.

Dr Jonica Newby

Apparently, whale sharks were seen off Albany! Is that right?

Dr Damian Thompson

Mm. Mm.

Dr Jonica Newby

Whale sharks! Do you know how far south Albany is? That is not whale shark country. That is white shark country!

NARRATION

Not that it's a laughing matter for the whale sharks.

Dr James Moore

They're effectively outrunning the hot water in search of cooler water and bait and feed to actually sustain them through that period.

NARRATION

The whole event lasted five months. It's our most extreme hot-water event on record.

Dr Jonica Newby

So there's actually something significant we should know about these rises that we've seen in sea temperature?

Dr Karl Braganza

Yeah, absolutely. Changes in ocean temperature around Australia really impact on the type of weather we receive.

Dr Jonica Newby

So, the warmer the water...?

Dr Karl Braganza

The warmer the water, generally the more rainfall that you'd expect.

Dr Jonica Newby

Well, still on our nation's circulation, what 100-year health check would be complete without blood pressure? I may be stretching the medical metaphor a little bit here, but I'm talking about sea level.

NARRATION

This is the glorious old West Australian port town of Fremantle. And it's home to one of Australia's oldest continuous tide gauge records.

Dr Jonica Newby

So this is the original Fremantle port's tidal gauge from 1897. Beautiful piece of machinery, isn't it?

And this is the latest tidal gauge. And, between them, what they chart is on average a 1.5mm rise per year since 1900.

NARRATION

Now, many of you may already be doing the maths on what that amounts to over 110 years. But, while you do that, I'm jumping back to the bottom of Australia - to Tassie's infamous Port Arthur, where there's a fantastic old marking that will answer that question. In 1841, the local storekeeper put in a tide mark, the oldest scientific one in the country.

Dr John Hunter

OK. It's just down there. There's a little...

Dr Jonica Newby

Oh! Right.

Dr John Hunter

..horizontal line with an arrow pointing down towards it.

Dr Jonica Newby

Yeah.

NARRATION

When the original records were rediscovered just a decade ago, Dr John Hunter was able to work out what's happened.

Dr John Hunter

OK, the total sea-level rise since 1841...

Dr Jonica Newby

Yeah.

Dr John Hunter

..is about 17 centimetres. And that's the length of that...

DrJonica Newby

Yeah?

Dr John Hunter

..that stick. If you compare that with Fremantle...

Dr Jonica Newby

Yep.

Dr John Hunter

..on the other side of the country, about 17 centimetres again since 1897.

Dr Jonica Newby

1897? OK, so that is a 100-year record, really, for Australia.

Dr John Hunter

Pretty well, yep, yep.

Dr Jonica Newby

This is how much it's gone up.

Dr John Hunter

Yep.

Dr Jonica Newby

17cm.

NARRATION

And this seemingly small rise has dramatically changed flooding. Last year, Port Arthur copped it like never before.

NARRATION

Using the historic Australian records, John Hunter has been able to show just how much each 10 centimetres rise in sea level has contributed to events like this.

Dr John Hunter

So, if you raise sea level by just 10 centimetres...

Dr Jonica Newby

Yeah.

Dr John Hunter

..you find you get a tripling of the number of flooding events.

Dr Jonica Newby

A tripling?

Dr John Hunter

And if you raise it by another 10 centimetres, it goes up by another factor of three, so that's a total of nine.

Dr Jonica Newby

So... so we've got nine times, effectively, the number of flooding events for structures at sea level than we did 100 years ago?

Dr John Hunter

Yes. That's right.

Dr Jonica Newby

I am surprised by that.

Dr John Hunter

It's a big change, yep.

Dr Jonica Newby

Yeah.

Dr Jonica Newby

So these are our current 'blood pressure', AKA 'sea level', readings. How are they looking?

Dr Karl Braganza

So what we're looking at here is basically from the satellite record from 1993. And we can see sea levels have risen everywhere. Red on this part up the top of the continent is a lot of sea-level rise. And the blue parts down the bottom is where we've had rather less sea-level rise.

NARRATION

Sea level naturally goes up and down a lot from year to year, but we can see from the Fremantle record the trend line is relentless.

Dr Jonica Newby

Which brings us last but not least to the final round of our 100-year health check - assessing our nation's state of hydration.

NARRATION

Well, lately, parts of Australia have been well hydrated. Overhydrated, in fact. My personal assessment is that it's barely stopped raining in the last two years. My cottage has sprung a leak.

Dr Jonica Newby

I'm thinking of calling it 'Newby Creek'.

NARRATION

Our dams around Sydney and Brisbane are full. And there have been record-breaking floods... in Brisbane, Victoria, New South Wales. But, again, IS it new? What do the trusty old rain gauges from the bureau say?

Dr Jonica Newby

So, now, the last two years' rainfall have been quite extraordinary, haven't they?

Dr Karl Braganza

They have. They've been record-breaking. So, over the last 24-month period, the two years, we've seen more rainfall in Australia for a 24-month period than we've ever seen in the historical record.

Dr Jonica Newby

And tell me - does this have something to do with the fact that the ocean and the air temperatures are higher?

Dr Karl Braganza

Normally, when you get a La Nina event you'll get almost record rainfall in Australia. This time, what we saw was record sea-surface temperatures around Australia. And so we've got basically a perfect storm. We've got a La Nina event. We've got global warming going on in the oceans around Australia. And then we've got this record rainfall as well.

NARRATION

But you'll see there's one part of Australia noticeably absent from this acute attack of fluid retention. It's my old stamping ground - the south-west of WA... which is where I am now, down amongst the karri trees. Well, underneath them, actually - inside glorious Jewel Cave.

Dr Jonica Newby

OK, so this is what I came here to show you. You see this black line? That's actually a water line, the high water mark from the late '60s. This was once a lake. Up to here. But, ever since then, the water has just drained away.

NARRATION

The last of the water disappeared by the year 2000. And it's the same sad story across the region. The caves of Margaret River have lost their lakes and streams. Land use changes have compounded the problem, but this is a symptom of chronic dehydration.

Dr Karl Braganza

So what we've got here is basically rainfall during April to November. And, in the last 15 years, in particular in the south-east of the continent, here, is about a 10% to 20% reduction in that rainfall.

Dr Jonica Newby

That much, yeah.

Dr Karl Braganza

That's right. And over here in the west we've seen the same thing, but that's actually occurred since about 1970, so they've had almost about four decades with much less winter rainfall than they used to have.

NARRATION

And now the big summary. What has happened to our weather?

Dr Jonica Newby

Well, we're ready for the final report in Australia's 100-year health check. So, hydration?

Dr Karl Braganza

Wetting up north, in the Tropics. Longer-term dehydration across the south, particularly in south-west WA.

Dr Jonica Newby

OK. Circulation?

Dr Karl Braganza

Sea level's increasing all around Australia. Um... not lapping at our toes yet.

Dr Jonica Newby

Finally - temperature.

Dr Karl Braganza

Temperatures around Australia have risen by about a degree. Um, less chills, more fevers. And some regional variation in that as well. So some regions are heating up more than others.

NARRATION

Essentially, what the records show is that global warming isn't something that's coming - it's here in our backyards already. It's pointless now to ask, 'Is this climate change or natural variability?' What we see is one acting on top of the other.

Dr Karl Braganza

So, every parcel of air, every ocean current, every weather system is now about a degree warmer. And when you go through and do the physics, that's actually a hell of a lot of energy added to the climate system in general.

Dr Jonica Newby

You know, of all the things I learned on this investigation, it was that comment from Karl that really struck me. It was like, 'Aha! I finally get it.' There's one degree of extra heat across the whole planet. That's just a lot of new energy in our weather system. What happens when you add another degree? And another?

NARRATION

So what WILL happen in the future? Well, I'm obviously going to have to spend some money on a retaining wall. And, like the rest of us, I'll try to do my bit. But I'll continue to toast my sunset, pray to my snow gods and get as much joy as I always have out of the parts of Australia I love. I do think I should do so with eyes wide open, though, and not pretend there's no change to see.

Fish photos provided courtesy of Redmap and were taken by the following photographers:

* Rick Stuart-Smith (Reef Life Survey)

* Antonia Cooper (Reef Life Survey)

* Scott Ling

* Graham Edgar (Reef Life Survey)

* David Maynard (QVMAG)

* John Keane

* Erik SchlÃ¶gl (Erik SchlÃ¶gl Photography)