Earth’s climate has never been of a fixed state; over the millions of years of Earth’s existence, it has changed many times in response to a diversity of natural causes. However, when people talk about climate change today, they mean the palpable changes in temperature over the last 100 years.
The history of the scientific discovery of climate change began in the early 1800s when natural changes in paleoclimate (also palaeoclimatology) were first suspected and the natural greenhouse effect first identified. Palaeoclimatology is the study of climate changes taken on the scale of the entire history of Earth. It uses records from ice sheets, tree rings, sediment, corals, shells and rocks, to determine the past states of the climate system on Earth.
Scientists think like detectives. They investigate the clues in order to find evidence that can give them better idea to understand the climate; they use several ways to collect this evidence. This process has started a long time ago. However, the procedure itself has differed from the past to the present. Some scientists invented methods and tools to study Earth's temperature, such as Weather satellites and stations and such, while others used tools such as ice cores, Sediment Analysis, etc.
Investigating the Past
- Ice Cores: Some scientists study ice as a key to understand weather. But not just any ice; they study the ice coming from glaciers that have been around for a very long time. They cut pieces of ice and look for air bubbles that were trapped in the ice hundreds or even thousands of years ago. The air bubbles help them discover what the climate used to be like on Earth. The evidence they uncovered was the creation of a historical record of regional temperatures and greenhouse gas concentrations dating 160,000 years back.
- Sediment Analysis: Sediment is the earth and rock that has built up in layers over time. Sediment layering provides information about where glaciers have been in the past. Ocean sediments provide a map of how ocean currents have flowed in the past. Fossilized pollen found in sediment layers tells us where different plants had grown in the past.
- Tree Rings: You can tell how old a tree is by counting its rings because it grows a new ring every year. Tree rings can also tell us how much precipitation fell each year in the place where the tree lives. Precipitation is rain or snow or any other moisture that falls to the Earth. Scientists study the sizes of tree rings; the different sizes of the rings tell us about the changes in temperature and precipitation.
Investigating the Present
- Weather Stations: help to find out the temperature on the surface of the Earth. They use special thermometers that show the temperature. It can also present how fast the wind moves and how much rain falls on the ground during a storm.
- Weather Satellites: are launched into space to send back information to scientists about Earth's weather and temperature.
- Weather Balloons: are released to float high up into the atmosphere; they carry special instruments that send all kinds of information about the weather back to Earth.
- Ocean Buoys: are objects that float on water, and are often used to warn boats away from dangerous places in the ocean or a river. But some buoys have special instruments on them that can tell the temperature and other atmospheric conditions.
Most scientists agree that global temperatures will rise still, depending on future emissions of greenhouse gases, which is not a natural cause, but a manmade one. If temperatures increase with high rates, changes in climate are likely to be so extreme that they will be difficult to cope with.
References
butnowyouknow.wordpress.com
direct.gov.uk
epa.gov
manicore.com
news.bbc.co.uk
wikipedia.org
*Adapted from an article published in the PSC Newsletter, Summer 2010.