1. IMPACT 3: Sea level rise and Ocean acidification

2. IMPACT 3: Sea level rise and Ocean acidification
The sea level rises in response to warming temperatures for two reasons.
First, as grounded ice melts, the melt water runs into the ocean, increasing the total amount of water in the ocean, and therefore, sea level.
Second, water expands when it warms.
The 2007 IPCC report predicted increases in sea level of several tens of centimeters over the next century.

3. A significant fraction of carbon dioxide (CO2) emitted to the atmosphere by humans ends up in the oceans.
In the liquid environment of the ocean, CO2 reacts with water and is converted into carbonic acid, the same weak acid found in soda water. The net result is that, as the oceans absorb more and more CO2, the oceans will become more acidic.
In fact, since the industrial revolution, the absorption of carbon has lowered the ocean’s pH by about 0.1. At present, the ocean is now more acidic than it has been for more than 20 million years.

4. Atmosphere-Ocean Carbon Exchange
One of carbon dioxide (CO2)’s most
important properties is that it readily
dissolved in water.
Once it has dissolved in water, CO2 can
be converted to carbonic acid (H2CO3) by means of this reaction:
CO2 + H2O H2CO3 (weak acid) (5.3)

5. On the pH scale, which runs from 0 to 14, solutions with low numbers are considered acidic and those with higher numbers are basic. Seven is neutral. Over the past 300 million years, ocean pH has been slightly basic, averaging about 8.2. Today, it is around 8.1, a drop of 0.1 pH units, representing a 25-percent increase in acidity over the past two centuries.

6. Glaciers melting

7. All liquid expands on heating and contracts on cooling