I’ve always loved water. My favourite sport is swimming, because of how it feels to have water holding you up. And when I was young, any time it rained I’d run outside and just walk for ages in the rain: I loved the smell and the cool of it. Admittedly, rain was a rarity in my childhood, since I grew up in New Mexico in the US, which is all mountains and desert. I can see why here in Ireland, where rain is so much more common, you see fewer people rushing to the streets each time it rains. But in my desert home, one of the things I found fascinating is that water has a story, a history just like us, it has somewhere it came from and somewhere it’s going. When we see the rain fall, it’s evaporated from the ground, from lakes, from the sea. And that same rain will be absorbed by the ground and stay in it before rising again, or freezing into ice caps, or melting and flowing again to the sea. Here in Ireland, the clouds come in off the ocean, so the water in our rain is evaporated sea water.
We can think of the water on the world like the water in our own bodies. We can run and get sweaty, and the water on our skin evaporates away. We can drink in water, filling our insides the same way that aquifers under the surface of the earth are filled with water. And then we can release that water given time, the same way that solid land loses some of its water to the seas. But because the earth is so big, it also has weather on its surface, clouds and rainfall, and as far as I know I’ve never sweated enough to make it rain.
But how quickly water moves through this cycle depends on the weather, the same way it does for our bodies. You sweat more when it’s hot and humid, like now, and less if it’s cold or dry, right? Well water is affected the same way, by how warm the surface of the earth is. In hot conditions, more water will evaporate off the earth’s surface and off of plants, which can stimulate more weather like rain and thunderstorms… unless it’s very dry! So where I grew up, desert plants have to work really hard to hang onto water, because it’s such a precious resource and the heat and dryness cause it to go away really quickly. Plants here don’t have that issue, as there is plenty of water to go around!
We are changing how the water cycles through our world, though. When people build dams, cut down forests, pasture animals, build cities, or burn fuel for energy, that changes where water can flow and how long it stays in the air. All of our activities affect the flow of water through the sky, the sea, and the earth.
In fact, greenhouse gases from our human civilization are causing the atmosphere to trap more heat from the sun, so that our planet is gradually warming up. It’s a slow process, taking decades for the world’s temperature to rise even a degree on average, but it’s been going on for awhile now. So even though we are trying to switch to solar power away from things like coal power, our planet will keep warming up. Sea levels will go up, and we’ll have warmer summers and rainier winters. Here in Ireland, it might be nice, as long as you don’t live right on the sea. But in New Mexico, it’s already difficult to grow food and stay cool during the summer, so the extra heat might make it very hard for people to live there. But the important thing about the future is understanding it so you can plan accordingly… for example, by moving to Ireland!