Question of the Week

Will global warming raise water levels in rivers?

Will global warming raise water levels in rivers and streams as well as just the sea? Jack Stowe, Lincolnshire

Helen Scales -   Well what’s going on in the rivers and streams and lakes and fresh water inland is a different process than in the seas because what they rely on mostly for the levels of them is the rain.  It’s all about whether it’s going to rain more or less, and one of the things we really know about climate change and what’s going to change in the future is that there’s going to be a difference in how different areas respond, some will become drier, there will be less rain, and some will become wetter, there will be more and we are already seeing this and in some areas like Australia, we are seeing huge amounts of droughts, rivers are drying up and that’s likely to become even more prevalent in some areas but there will be also rain increasing in some parts of the world.  So it would definitely vary and not be a sort of general increase in sea level that we will see and the sea levels are rising of course because actually as that huge amounts of water heats up it will expand and the sea levels will go up and also more water will pull into the oceans and from the melting icecaps and things like that.  

So really the picture in the rivers will be very regionally diverse and it would depend on where you are in the world.  

Chris Smith -   So the bottom line is rivers are down to rain, sea level is going to rise anyway because of thermal expansion and ice melting.

April 2009