Have you ever wondered where the wind comes from? Or have you been noticing the wind more than you used to? What if I told you that the wind you feel on your face is determined by the temperature beneath your feet?

I went to Monash University for my undergrad studies, and there was a notoriously windy part of campus at the bottom of the Menzies Building - the largest structure on campus at that time - which acted like a giant sail, funnelling the wind along the causeway at the bottom. Witnessing first year students battle through the wind tunnel was one of the most unifying experiences on campus, especially because revolving doors had been installed on the Menzies building to deal with the incessant wind channelling past the entryway.

I was studying geology so I was pretty into earth systems and it has always fascinated me how we, humans, have become so detached from the ‘natural’ world that we believe things like the Menzies wind tunnel are just quirks of campus. But when you study rocks you gain a whole new appreciation of the landscape and how it is the formations on earth’s surface that dictate what life is like around them.

For instance, the weather is controlled more or less by mountains and the oceans - one cannot separate any part of the earth system because it is inherently interconnected. The wind tunnel under the Menzies building was the consequence of building a 40 metre high structure in the middle of what was a sheep paddock, and before that low coastal shrubland. The building runs east-west meaning that it collects the prevailing south easterly winds that blow across Victoria during the winter, and the warm north-westerly winds that demarcate summer in Southern Australia.

Wind is the one weather event that seems to remind humans that we are animals just like the rest of the creatures on this planet, we’re a part of the system, it’s just that we’re the most effective communicators between our species. We were able to form complex thoughts because of our ability to form sounds that we collectively decided were words. As generations go on, we invent new words to describe all of the things happening. It’s not that we’re any smarter than the generations before, it is that we can utilise all of the things that they created. It is also why it can be reductive to make comparisons to the actions of people long ago - everything seems clearer when viewed through hindsight. But wind, it has a way of scaring the dogs, it makes cats nervous, and makes horses go crazy. Next time it’s a really windy day observe the people around you, do you notice how erratic people get?

Because of this phenomenon wind has always fascinated me, to the point I’ve been reading a lot about the earth systems which control the wind. I heard a talk once that outlined how the warming of the atmosphere is moving the jet streams which engulf the world. As the planet warms, the northern polar stream will likely shift southwards and put continental Europe into an ice age whilst the north of Africa becomes uninhabitable with heat. If you’re scared of turbulence when you’re in a plane, then I encourage you to look up what jet streams are because typically all turbulence is caused by crossing a jet stream. There is a major one that crosses Australia which is why you always get turbulence when flying from Melbourne to Brisbane.

But jet streams are high above the ground, they have minimal influence over what we feel on the earth’s surface. The wind we feel on our faces is more closely dictated by the soil and the hills around us because wind is created by differences in pressure - and pressure can be thought of as a change in temperature. Think of a time when you’ve opened the door of to a warm room and felt the air blow out onto your face, what has occurred is the higher pressure in the room has made it warm and when you’ve opened the door that pressure is ‘released’ and tries to make an equilibrium with the cooler air outside. An air conditioner works by drawing hot air out of a room by reducing the internal pressure of the room and then passing that air over a refrigerant gas to speed up the process and then pumps the air outside.

So how does this relate to soil?

Soils are like a blanket on the surface of the Earth meaning it is influenced by the heat generated beneath the surface as well as above. As the ground heats up, it also warms the air above it, and when this happens the air becomes lighter and expands which raises the air up. Conversely, cold air is denser so when the warmer air rises up the cooler air above sinks down to fill the space left by the rising hot air. That moving air is wind.

The greater the difference between the temperature of the rising warm air and the sinking cold air the stronger the wind. So when you hear the weather report and they say a “low pressure system is moving over the state” it means a mass of cold air is coming. If the temperature on the ground is cold, then it will likely rain. But if the temperature on the ground is hot then you can guarantee there will be wind. Or if it is a low pressure system, aka cold air, meeting with a high pressure system, aka warm air, then that’s a recipe for a storm because the warm air will push the cold air down. This is the ‘cool change’ you feel before a storm hits. Look up the laws of thermodynamics if you want to know about this phenomenon in detail.

All you really need to know when hot air rises, cold air sinks, and that equals wind.

This is why wind is typically cold. But when you feel hot northerly winds in summer, it is scary because it means the high pressure systems nearer the equator are so hot that they push past the jet streams trying to find some low pressure to expand into - which is typically Victoria during summer. And if there are bushfires then they’ll be fanned by this wind and go off like a frog in a sock.

Now that you’re an expert in wind generation, we can talk about the depressing stuff.

Soil temperatures in Australia are rising, meaning that we are experiencing more wind than we have seen before.

The increase in soil temperatures in combination with rising ocean water temperatures mean that evaporation is occurring faster than ever before. This is causing intense storm cells are being felt which bring large amounts of rain in a short period of time. This has the negative effect of further stripping the top soil away through erosion which results in even more temperature variation.

In science this is called a negative feedback loop; a process in which one event increases the likelihood of another which in turn causes the event to occur again.

So what can we do about it?

There are several but here are three simple ones to do at home: