1.3.1 How do scientists measure climate change?
Questions to discuss with students for activating their pre-knowledge
- What do you think – how do we know that the climate is changing?
- What do you think or know – what are the methods to study the change of climate?
- What kind of criticism have you heard about measuring climate change? How would you react to that criticism?
What are the most common methodological approaches for climate studies i.e. how we know climate has changed and is currently changing?
To study the climate, we need long-term observations of the weather. The series of observations made with scientific instruments are only a few hundred years old. Therefore, scientists use a wide variety of indirect methods to get an idea of the climate of the past. For example, the sediments of the oceans and lakes are like natural archives that contain hints about the climate of the past. We also find traces of past climate in the glaciers and to study the climate more than million years ago, we need to look for traces of ancient sedimentary rocks. The further we go back in time, the more inaccurate our data will become.
We also try to look to the future. We study the climate of the past in order to understand the basic regularities of its formation and to be able to predict the climate of the future. In the weather forecast, we can predict the weather for the next few days quite accurately, but the forecast for future climate change becomes more inaccurate the more we try to look into the distant future. Present climate changes can also be analyzed from the air, see eg. https://www.csiro.au/greenhouse-gases/.
The research carried out by many scientists on the Earth’s past climate and the predictions made on the basis of it are summarized in a report prepared every few years by the Intergovernmental Panel on Climate Change (IPCC). On this basis, policy recommendations are made to decision-makers to help prevent the negative effects of climate change. See also how the different climate indicators in your home region will change in the coming decades https://interactive-atlas.ipcc.ch/.