Climate change is not just warming the air — it is also changing the ocean. The ocean covers more than 70% of Earth’s surface and plays a key role in controlling our climate. As global temperatures rise due to greenhouse gases, the ocean is affected in many ways that can harm both marine life and people.
One major effect is ocean warming. As the atmosphere heats up, the ocean absorbs much of that extra heat. Warmer oceans can cause coral reefs to bleach, which means the coral loses its color and becomes weak or dies. This hurts fish and other animals that depend on coral reefs for food and shelter. Warming seas also affect fish migration patterns and change where certain species can survive.
Another result of climate change is melting ice and rising sea levels. When glaciers and ice sheets melt, they add more water to the ocean. Warmer water also expands. Both of these things cause sea level rise, which can flood coastlines and damage homes, cities, and wetlands.
Climate change also causes the ocean to become more acidic. This happens because carbon dioxide (CO₂) from the air dissolves in seawater, forming a weak acid. This ocean acidification makes it hard for animals like oysters, clams, and some plankton to build their shells. If these creatures are harmed, it affects the whole ocean food chain.
Changes in ocean temperature and chemistry also affect weather patterns. For example, stronger hurricanes can form over warmer waters. Ocean currents, which help move heat around the planet, can also change and lead to unusual weather in places far from the ocean.
Fun Fact: The ocean has absorbed more than 90% of the heat trapped by greenhouse gases since the 1970s!
What causes the ocean to warm up?
Less rainfallSunlight getting strongerGreenhouse gases trapping heatVolcano eruptionsWhat is coral bleaching?
When coral changes shapeWhen coral turns white and weakensWhen coral grows fasterWhen coral moves to landWhat does rising sea level NOT do?
Flood coastlinesCool down the oceanDamage wetlandsThreaten coastal citiesWhy does ocean acidification happen?
Due to melting glaciersFrom underwater volcanoesBecause of carbon dioxide in the airFrom too much saltWhat are some animals affected by ocean acidification?
Sharks and whalesDolphins and turtlesOysters, clams, and planktonCrabs and penguinsHow does ocean warming affect fish?
Fish get strongerFish swim to new placesFish grow fasterFish stay in one spotWhat is the main idea of the passage?
Oceans help fish grow fasterClimate change has no effect on oceansClimate change is causing big changes in the oceanWeather changes the ocean’s colorHow might climate change lead to stronger hurricanes?
By freezing the airBy changing ocean currentsBy warming ocean watersBy moving the land