IamA Meteorologist for Australia's national weather service, the Bureau of Meteorology. We need to talk about climate change...AMA.

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Sure. Done. http://imgur.com/Qzj5xo2. Is that ok?

So we notice that the climate is changing. Hotter in some places. Cooler in others. Strange in most. What's to say that these changes are not just part of the natural cycle of change of the planet. If it is indeed our own doing, seeing as a species we are very resilient, what's the impetus to go ahead an make changes to stop/slow/reverse climate change? Last question is it reversible?

There is a slew of evidence this isn't just natural variability. If it is natural variability it still needs a trigger.

In the past, differing solar output has been one natural trigger. Solar output in the last 30 years has actually gone down, while global temperatures continue to rise, so we know this cannot be the case this time. Also, if increased solar output were to blame, we'd expect all layers of the atmosphere to be warming. In reality, only the troposphere is warming (where greenhouse gases are mostly found), while the temperature in the stratosphere is actually decreasing.

Additionally, the rate of change of temperature in the last 100, and particualrly the last 50 years is unprecedented throughout human history, and is consistent with the observed rise of greenhouse gases, in particular CO2, in the atmosphere.

Warming according to your "homogenized" figures, or actual data?

How do you explain the slowing of warming despite record CO2 output?

We're in a negative phase of the Pacific Decadel Oscillation (PDO) at the moment. Negative phases have been attributed to a slowing of warming in the past century. Check out this graph, it's pretty compelling http://www.nature.com/polopoly_fs/7.14906.1389714879!/image/Warming.jpg_gen/derivatives/lightbox/Warming.jpg

How do you feel about our current governments stance to climate change? Is there anything we can do to change Tony Abbott's mind?

The Government's current official stance on climate change is that it's anthropogenic and that it's happening, thankfully. Now action must be taken.

What about the carbon tax?

It wasn't helping. Big polluters could get around it anyway. We need significant Government investment in renewable sources to move toward a 0 carbon economy.

Which countries do you think are being the most responsible with regards to climate change?

Which corporations are having the most positive impact on climate change?

China is having a heavy impact of late, with their turn toward fossil fuels. Obviously the US is a major contributor.

Change of living is obviously not a realistic option. People are not going to change until its too late which it might be already. Is there a more realistic solution or is 'hoping' for change our only chance?

Well, that's why I'm on here doing this AMA. We just need to educate people. We need to let them know it's definitely happening, how we know this, and what will happen to us and our planet if we don't act on it as soon as we can. I'm sick of the inaction, this is me doing my part in trying to get the ball rolling.

How do you respond to people who do not take climate change seriously or even claim that it isn't real?

It's my job as a climate scientist to educate them, that's all I can do. It's frustrating that people believe these things, but often it's just because they aren't wise to the facts. What's even more frustrating is those deniers who refuse to accept indisputable evidence.

What can I do as a college student do to help slow down the effects of global warming?

Spread the word. Organise and attend rallies. Call your local politician. Go higher up if you can. Become educated.

I use your website to check the weather all the time. You guys predict rain way more than it actually occurs. What's the deal?

(But seriously I love you guys. Also I work in the same building as you in one of the Australian capital cities. We maybe even catch the same lift on work days. Hi!)

Heya! Which city are you in?

Rain will be predicted when precipitation is expected in ANY part of an urban area at ANY time of day. Showers of rain (from convective clouds) can be espcially localised, so even if you may not have experienced rain, others in your may have.

1) Why does it seem like much of the argument revolves around saving the 'planet' rather than saving ourselves?

The planet will continue with or without us, life will thrive in the face of drastic climate change, nothing we do will match the Permian extinction in terms of loss of diversity yet current diversity persists.

Let's be frank, we aren't worried about saving the planet, we are worried about saving ourselves. And the only way to do that is to maintain biodiversity in a way that environments and ecosystem services function as we are accustomed to.

2) Do you think individual contributions such as turning off the hot water element when you go on vacation should be relied upon or that legislative changes are the only thing that will make a significant difference? Particularly in industrial practices. Riding my bike to work seems ineffectual when the lack of regulations over the shipping industry emissions means that two dozen cargo ships emit more pollution than my whole continent.

1) At the rate we are warming now, it's certainly not just ourselves that are in danger. Many animals are unlikely to be able to keep up with the warming from an evolutionary perspective. But yes, in the end, it is us who will suffer most.

2) Individual contributions are great, but we need to tackle this with legislative changes, absolutely. And they need to be worldwide and coordinated. We need to move towards a 0 carbon economy as soon as possible. Doing this is only estimated to reduce worldwide revenues by 3-11% over the next century, so it is quite plausible.

What can we do in conjunction with you or as individuals to spread the knowledge in a simple fashion to uneducated people on the matter? Is there a simple way of explaining it through social media for example? Please let us know what we can do to help because I'm sure if you got all of us to portray a message through any social media platform, the impact would be at least somewhat profound.

I'd like to get a campaign started, but I'd have to brainstorm some ideas for that. If we can get something as big as the ice bucket challenge spreading through social media, the impact could indeed be profound. Does anyone have any idea?

The best way to educate those who are skeptical is by knowing the facts, knowing the arguments against those they are likely to throw at you, and explaining these arguments to them clearly and calmly. It's also important to let them know the potential impacts for our generation and future generations to come. Even if we switch to a 0 Carbon system now, some of these impacts are already inevitable. That scares me.

Two questions, if I may.

First, what do you make of this argument? Yes, climate change is real and human caused to a significant degree, but the kind of action we'd need to take to reverse it is so difficult and expensive that we'd instead be better off working on mitigation and adaptation. In other words, it seems the only way to "solve" climate change is by immiserating ourselves. For wealthy countries like the U.S. and Australia, the impacts just aren't likely to be large enough to justify that sort of action.

Second, what's your response to the claim from climate deniers that there's a recent "pause" in warming trends as global average temperatures have leveled out over the past 10+ years? Is there, in fact, a pause, and if so, what's the explanation for why most climate models failed to predict it?

That's simply not true. If we keep going the way we are, cities around the world will be under water. Addressing climate change and moving toward a 0 carbon economy will reduce revenues worldwide by between 3 and 11% over the next century.

Plus, if we burn off all our fossil fuels, a doomsday scenario is eventually possible, with a collapse in the AMOC, an ocean current which is vital in heat transport from equator to poles. Without this very little of the planet is likely to be livable.

What's your thoughts on the things that Marohasey is writing about. Is the BOM faking evidence to support climate change?

We changed the readings on two stations in Australia, and we had reasons for it. This isn't going to affect the overall temperature trend in Australia in any way. We're scientists, we aren't out to cook data, we don't have any kind of ulterior motive here. Our only goal is accurate and scientific analysis of the climate and weather.

Skeptics of course don't mention the fact that, when calculating temperature trends in Australia, we revise many of our urban observations down, in order to account for the urban heat island affect.

How is it that meteorologists can't accurately forecast the weather a week in advance, yet it was accurately forecasted back in April that we (in Midwestern U.S.) would have a cooler than average summer?

That prediction was likely based on the North Atlantic Oscillation, an atmospheric wave with two polarities. Depending on its likely polarity, predictions on warmer of cooler than average seasons can be made with a moderately high degree of confidence (I believe around 80%)

What direction do tornados spin in Australia?

Tornadoes can actually spin either way in either hemisphere, as they are on far too small a scale to be affected by the coriolis force.