Wildlife Wednesdays: Mass Extinction, Part Three
Earth is going through its 6th mass extinction and it is taking a huge toll on plants, animals, and their habitats. The trend seems to be from hotter oceans, deforestation, and climate change, which is causing animal populations to decrease at an alarming rate. Today's article will discuss the final factors showing why we are possibly in this mass extinction.
Oceans are absorbing a lot of excess heat (at about 93%), because of the increase in greenhouses gases in the atmosphere This is killing off marine species and coral reefs. Scientists are realizing that oceans are heating up 40% faster than they previously thought! Higher ocean temperatures and the acidity of the water is causing coral bleaching. This occurs when coral reefs expel their algae in their tissues and it becomes white. As a result, the coral dies. About 50% of the world's coral reefs have died over the past 30 years.
The problem is not only with oceans but with freshwater lakes and rivers as well. A study done in 2013 showed that 82% of native freshwater fish species in California were at risk for extinction because of the warming freshwater. Most native fish populations are expected to decline, or even become extinct, because many fish species need waters that are colder than 70 degrees Fahrenheit to thrive.
With warming oceans, this can cause sea level rise, which has already impacted several animal species around the world. The present day global sea level is 5-8 inches higher than average than it was in 1900, according to Smithsonian! In February of this year, Australia's environmental minister officially declared the Bramble Cay melomys to be the first species to be extinct because of sea level rise. Warming oceans are also leading to ice melt in the Arctic and Antarctic. The Antarctic ice sheet is melting nearly 6 times as fast as it did in the 1980's; also, Greenland's ice is melting 4 times faster than it was 16 years ago, according to a study. Sea level rise threatens 233 federally protected animal and plant species in 23 coastal states across the US, according to a report from the Center for Biological Diversity. It also noted that 17% of the threatened and endangered species are vulnerable to rising sea levels and storm surges.
If the climate continues to change, the animals and plants of South America and Oceania are to be the hardest hit, while North American species are at the lowest risk. Scientists are still arguing about whether the Earth is "truly" in a mass extinction. Some say we are not quite there yet. A 2014 study, done by several people issued in Science Magazine, stated that current extinction rates are 1,000 times higher than they would be if humans were not around. They go as far as to say that human-caused extinctions probably would not be happening at all (or very little) if we did not exist.
