6 Ways Climate Change Affects The Ocean
Quick Refresher on How Global Warming Works:
(feel free to skip this opening paragraph if you're already across this)
Once light from the Sun passes through the Earth’s air and clouds, much of it bounces off the Earth’s land surface back towards the sky in the form of infrared heat. About 90% of this heat is then absorbed again by certain atmospheric gases and radiated back down towards the surface. This means the heat is essentially trapped inside the Earth's atmosphere, warming the planet like a giant greenhouse, hence the term “greenhouse” gases.
The greenhouse effect occurs naturally and is a key contributor to Earth’s stable temperature and ability to support life. However, as humans pollute the air with more carbon dioxide than nature intended, we are effectively putting this process into hyperdrive and warming up the planet at a rapid pace.
Luckily for us, our oceans have been absorbing most of the heat but at what cost?
1. Increased Sea Surface Temperature
The surface temperature of our oceans increased dramatically throughout the 20th century. This has created a recipe for disaster when it comes to hurricanes and thunderstorms. Warm water is more easily evaporated than cool water. So with warmer sea surface temperatures, storms can turn more water into vapour and can therefore carry more heat (stored in the vapour) into the upper atmosphere. This can create a hurricane by lowering the air pressure, causing winds at the oceans’ surface to spiral inward and pick up speed.
2. Coral Bleaching
Coral and algae have a mutually beneficial relationship. The coral provides the algae with a protected environment and the compounds they need for photosynthesis. In return, the algae produce oxygen and help the coral to remove wastes. When coral is stressed by changes in conditions, such as an increase in ocean temperature, it expels the algae living in its tissues, causing it to turn completely white. This process is called coral bleaching.
When a coral bleaches, it is not dead, but is under more stress and is more likely to die.
3. Fish Migration
Steadily rising ocean temperatures are forcing fish to abandon their traditional habitats in search of cooler waters. It seems that these migrating species of fish are now swimming ever closer to the earth's polar regions in the search for better oxygenated water and a much fuller source of food.
This can have devastating effects on the eco-systems left behind, as key links in the local food chain disappear. Fishermen’s livelihoods are also being disrupted, as fisheries regulators scramble to incorporate climate change into their planning.
4. Rising Sea Levels
The change in sea levels is linked to three primary factors, all induced by ongoing global climate change:
Thermal expansion: When water heats up, it expands. About half of the sea-level rise over the past 25 years is attributable to warmer oceans simply occupying more space.
Melting glaciers: Persistently higher temperatures caused by global warming have led to greater-than-average summer melting of mountain glaciers.
Loss of Greenland and Antarctica’s ice sheets: As with mountain glaciers, increased heat is causing the massive ice sheets that cover Greenland and Antarctica to melt more quickly.
5. Ocean Acidification
When carbon dioxide is absorbed by the ocean, it dissolves to form carbonic acid. The result, not surprisingly, is that the ocean becomes more acidic, upsetting the delicate pH balance that millions and millions of organisms rely on.
Since the Industrial Revolution, our seas have become about 30 percent more acidic, a rate not observed in 300 million years.
6. Coastal Flooding
Climate change exacerbates coastal flooding from a storm surge as the storm rides on higher sea levels. Also, coastal coral reefs and seagrass meadows that rely on shallow water in order to receive sufficient sunlight to photosynthesize are also in danger of “drowning” as a result of rising sea levels.