For 2.5 million years the Earth’s climate has fluctuated cycling from ice ages to warmer periods. But in the last century, Earth’s temperature has risen unusually fast about 1.2 to 1.4 degrees Fahrenheit. Scientists believe it is because of human activity that is driving the temperatures up a process known as global warming. Ever since the industrial revolution began, factories, power plants and eventually cars have burned fossil fuels such as oil releasing huge amounts of carbon dioxide and other gases into the atmosphere. These greenhouse gases trap heat near the earth through a naturally occurring process called the greenhouse effect. The greenhouse effect begins with the Sun and the energy it radiates to the earth. The earth and the atmosphere absorb some of this energy while the rest is radiated back into space. This greenhouse effect is being intensified by the extra greenhouse gases that humans have released. As long as industrialized nations consume energy and developing countries increase their fossil fuel consumption, the concentration of greenhouse gases in the atmosphere will continue to rise.
Temperature plays a critical role in determining the distribution and diversity of marine life. It is critical to reef building and controls the rate of coral reef growth. Like all marine life, corals have evolved over many thousands of years within limited temperature ranges. When these limits are exceeded, corals are put under thermal stress, causing them to expel the tiny algae that live within their tissues that they need to survive. The process called bleaching means only a white skeleton where before there were fibrin colors bleached. Coral bleaching is not always fatal, but has been one of the main causes of coral death around the world in the past two decades. Bleached corals are not necessarily dead unless if conditions do not ease within weeks, the corals eventually starve and die. Since 1910–1929 average ocean temperatures around Australia have warmed by 0.68 degrees Celsius. Records were set in the summer of 2012–13 when the hottest sea surface temperatures for the Australian region were recorded.