Climate Change

How do scientists measure the global temperatures’ change? Has there indeed been a warming pause in the last 15 years? What does global warming mean for the ocean? These and other questions are answered by Professor of Climate and Environmental Physics at Physics Institute of University of Bern Thomas Stocker.

When people talk about climate change I hear a lot the word “global warming”. I don’t like that term because it does not fully cover and comprehensively describe what we are talking about. We are talking about changes in all components of the climate system. That concerns most physical variables, that concerns also other areas like ecosystems. It is an all encompassing change at which we are looking now. But obviously it started from observing the temperature, and that is where the origin of this terms comes from.

One of the changes that almost goes unnoticed by the public is the acidification of the ocean. With the increase of carbon dioxide in the atmosphere , the ocean becomes more acid which means that marine organisms that create shells that need to calcify, to extract calcium carbonate from the water, they get a much harder time to build their shells in the environment that is more acid. Acidification is one of the largest scale- impacts with the longest time-scale that man is inflicting on this climate system. We know that once carbon dioxide is emitted and creates the warming in the atmosphere but also the acidification in the ocean, this carbon dioxide stays in the atmosphere for many millennia which means that the changes that we are bringing into the climate system today will be with us for a long time.

Like in any scientific endeavor, there are still many open questions. They don’t put fundamentally into question our knowledge on climate change. But they concern important issues that we would like to know better and better understand. …How the water cycle responds to the warmer world? Where are the areas that receive more water? What is the changing seasonality for example, in precipitation? These are important questions when it comes to trying to evaluate and estimate how the ecosystems – forests, vegetation, eventually food production will respond to climate change and what options there are for adaptation?