Notes for Water Resources

3.2.1 - The Hydrosphere (KQ2): Impact of Global Warming on the Hydrosphere

We have already had an introduction global warming/climate change in class...we have seen the evidence and know why it happens.  Now, we will discuss the effect it has on the hydrosphere in particular.

You may have heard of sea level rise as an impact of global warming.  But why would it happen?  If ice is water, even if it melted, wouldn't the sea level stay the same?  Well, no...because, the ice that we're concerned with is the glaciers and ice caps that are above the sea.  Take a look at the following picture of Sawyer Glacier in Alaska:

Yes, much of this glacier is under water.  If that melts, the sea level would stay the same...or maybe even decrease a bit since ice takes up more space than liquid water.  But...if the part that you see...the part above sea level melts, it will fall into the sea and increase the sea level...and drastically!

Also, if the ocean warms, the water will expand due to the increased movement of molecules, and the sea level will rise.  The following graphic shows the different ways sea level rises:

So...are we seeing this currently???  The answer is yes...just look at this graph:

You can see that the sea level is rising...and most estimates have it climbing even more dramatically in the near future.

So...why is this bad?  What are the potential impacts of rising sea levels?  Read this article from the Washington Post what's happening, what may happen in the future, and why.  Use this viewer from NOAA to see the projected sea level rise impacts on low-lying coastal areas in the US. Around the world, low-lying areas will become much more vulnerable to increase flooding, and coastlines will even move inward.  This has happened in Earth's past with climate change associated with ice ages coming and going, but those happened very gradually, also either before humans had populated the Earth or with very little human population to worry about.  The rapid pace at which we are adding greenhouse gases to our atmosphere is changing the climate too rapidly for us to be prepared for the change.  In fact, we are nearly as high on sea level as we have been in the last 400,000+ years...and we are projected to rise.  You can see evidenced published in peer-reviewed papers, along with carbon dioxide and temperature data below.

This video put out by NASA has some great visualizations and explanations of what has happened recently.

Read the highlights from the 2014 National Climate Assessment here to see the impacts climate change can have on our water supply as a whole.  Pretty scary stuff!

We'll get into climate change more in the atmosphere unit, but, if you want, explore the NASA climate change site here and the NOAA site here...the more educated you are, the more you care!