The sea level is rising, is climate change contributing to the increase? Dr. Chris Derksen, Research Scientist at Environment and Climate Change Canada, explains how and what we can except for the future.
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[Kerbens Boisette, Host, Ask a Scientist, Environment and Climate Change Canada]
Hello everyone! On today’s episode of Ask a Scientist we will be talking about our planet’s oceans and how they are directly affected by climate change, thanks to a question from Emily in Vankleek Hill, Ontario.

[Emily, Vankleek Hill, ON]
How does climate change affect the sea level to rise? And how much is it going up and what can we expect for the future?

[Kerbens Boisette]
Great questions, our climate change expert, Dr. Chris Derksen can certainly help us understand this better.
[Chris Derksen, Research Scientist, Environment and Climate Change Canada]

So, our question is, how does climate change cause sea level rise, and how much has it increased? And what can we expect in the future?
Well, over the 20th century, measurements made by surface observations, and measurements from satellites tell us that sea level has increased by about fifteen centimetres, and this increase is occurring at a rate of about four millimetres per year.
Now, this may seem like a small number, but when you accumulate four millimetres, year after year, decade after decade, it results in the measured amount of sea level rise that we've seen to date. And this increase in sea level poses a real risk to low-lying island countries, to coastal infrastructure, and the risk is increased by extreme events like storm surges and extreme tide events.
Now, there are two main drivers of sea-level rise related to climate change.
The first is that as our atmosphere has gotten warmer, the oceans have actually sucked some of the heat from the atmosphere into the top of the ocean, so this means, without the role of the oceans in storing some of that heat, we would experience even more global warming than we have to date. But these warmer ocean waters thermally expand, and this expansion means that sea level increases.
The second main driver of sea level rise is the melt of large ice sheets, so this includes Greenland and Antarctica, and smaller glaciers and ice caps in the Canadian Arctic as well.
So, as the water that was stored in solid form on these ice sheets melts, it pours into the ocean and results in sea level rise.
So, what can we expect in the future?
Well, climate models suggest that by the end of this century, we will experience an additional forty to eighty-five centimetres of sea level rise, depending on which carbon emissions pathway our planet goes down. So, that means decisions made about climate emissions policies in the future will have a direct impact on the amount of sea level rise.
What about longer time horizons?
Now, these sea level rise estimates are subject to what we call deep uncertainty, in that there's a lot of potential unknowns, but climate models suggest that by 2300, we could see an additional four metres of sea level rise. These are very dramatic increases that will have costly impacts on countries around the world.
So, sea level rise is closely connected to climate change, and it certainly will require adaptation in the future as our oceans continue to rise.
The next time you're in a coastal city, see if you can see any engineering projects that are underway to help protect these coastal regions and adapt to sea level rise.
So, thanks very much for your question. And keep them coming in.

[Kerbens Boisette]
Thanks Chris! So our oceans play a huge role in slowing down global warming but this also comes with it’s own consequences. It’s always a good thing understanding the world around us so we can make better decisions going forward to help fight climate change.
Keep your questions coming for the next, Ask a Scientist.
See you next time.