Sea levels can be defined as the average surface level for oceans around the world, these have been rising since the beginning of the 20th century. Sea level rise is mostly caused by global warming and thermal expansion. When water heats up, it expands slightly; when it is scaled up to large bodies of water like oceans, the change can be drastic. This heating of the ocean is created by human activity, mostly by the emission of heat-trapping gases.

These have increased global temperature by 1.4º F since the 1880s. According to National Geographic, sea levels have been rising 3.5 millimeters annually since 1990.

Sea levels have been changing for the last three million years, but they first started to rise alarmingly during 1993.

Sea level rise is caused primarily by two factors related to global warming: the added water from melting ice sheets and glaciers and the expansion of seawater as it warms.

Oceans are getting warmer mostly because of global warming, which is directly related to human activity. Heat-trapping gases such as carbon dioxide and smoke from burning fossil fuels are the main cause for this global warming. Since 1840, the levels of carbon dioxide have increased roughly 35 percent, this gas gets trapped in the atmosphere and later released into the ocean. This allows ocean waters to expand because of the movement of molecules.

With the rise of sea levels, come numerous consequences. One of them is the contamination of agricultural land and crops. When the ocean reaches land, its pH is different from the land’s, this causes contamination. Infected grounds cannot be harvested in. Nowadays, the ocean is also polluted from the trash humans leave behind. Garbage also has an effect on agricultural areas, which can lead to the production of less crops.

Other species can be affected by sea levels as well. Animals like shorebirds and sea turtles, which live on the beach, could have their homes flooded by rising shores. This is especially important for endangered species who can’t afford to lose any offspring. Their nests can be swept away by the ocean, leaving them in an environment where it is difficult to survive. For shorebirds, the rising sea could make them abandon their eggs and lead to their extinction. In many cases, this is where large population centers are located, in addition to fragile wildlife habitats. Therefore, people may become displaced and will need to seek safer homes. Even life farther inland is threatened because rising seas can contaminate soil and groundwater with salt.