Climate and Ice

Have you ever wondered what climate was like on earth hundreds or thousands of years ago? This is the same question that scientists are asking. So, one way that they can look into the past is by studying ice cores from glaciers to get an idea of what the climate was like, so many years ago. What's the difference between weather and climate? Weather is basically the hour-by-hour day-to-day changes that we see. You go on TV, and you watch the weatherman to see what it's going to be like in a few hours. Maybe even towards the end of the week. Climate is basically the overall average of what happens in an area. On a scale of years or decades or centuries. I see. So weather looks at one day while climate looks at the average of many days. Now this average tells us what it's normally like at a certain place. Let's take a look at Forks. No, not that kind of Forks. Forks Washington. From 2003 to 2009, it rained an average of 117 inches a year. Now this tells us that it's normally rainy in Forks Washington. Now let's compare this to Las Vegas, Nevada, where the average annual precipitation is only 4.13 inches. We can see that the climate in Forks is wet and the climate in Las Vegas is dry. Now that we understand how to determine climate, how do we find out what the climate was like on earth hundreds or thousands of years ago? This is where glaciers come in. What is a glacier? A glacier is basically snow that has accumulated over many, many years. It will drop down and it will stay there without melting, and it will just continue to snow year after year after year, piling up on top of itself. And as those accumulations occur, enough snow and ice will start to build up. So it starts off as snow at the top but then turns to ice at the bottom after so long and with enough pressure. Let's say that this bowl is a mountain basin. The first year there's a light snowfall. The wind blows dust, pollen, and other things found in the atmosphere onto the snow. The next year, there's heavy snowfall. And the volcano of a neighboring mountain erupts. The top layer of snow and ash adds pressure to the layer below. The weight of each new snowfall compresses the layers of snow below it, turning the older layers at the bottom to ice. This is how glaciers form. What do glaciers record? The glaciers are going to record year-to-year changes. There's all these sorts of things that we can look for within the glacier to see what the atmosphere was like. How many greenhouse gases were in the atmosphere at this time? They can also look at dust to see how dry or windy a place was at that time. Pollen. Was it wet? Was it dry? We can actually even see bomb testings, volcanic ash. They can see volcanic eruptions that occurred. This kind of information can really help us look into the past and look at climate. And what the atmosphere or the climate around that region was like. Where are glaciers found? Surprisingly enough, you can find glaciers all throughout the world. When people think of glaciers, they automatically think of the Arctic or the Antarctic, which is true. There are glaciers there. But people don't normally think that the tropics are areas that are going to have glaciers. But in fact, they do. India in the Himalayas, the South America, and there are even glaciers on Africa. Like Mount Kilimanjaro, you just have to go high enough up into the mountains where the snow is actually going to fall and accumulate. It's important to study several different locations rather than just one, mainly because the scientists want to get an idea of what's going on globally. So if we're going to look at the climate of the earth in the past, we can't only go to one location. Something might have happened there that didn't happen elsewhere. We need to go to several different locations and then use the information that's found there to sort of bring it together so we can see exactly how the climate has changed on earth as a whole. So what we've learned today is how a glacier can really give us a look into what the climate was like on earth so many years ago. Many scientists are trying to use this information and collect it before it disappears. So they can see how earth's climate has changed over hundreds or thousands of years.