Representative image of an island in the middle of an ocean.
Credit: iStock Photo
The world is now familiar with many tell-tale signs of climate change in nature but more of them are emerging in different areas. One that has attracted attention recently is the change in the colour of oceans. The prestigious science journal Nature has reported that the colour of oceans is changing from blue to green in many parts of the world and that could be because of climate change. Over half of the world’s oceans — about 56% — have changed colour in the past 20 years. The total area of oceans that has turned green is more than the total area of land on earth. The ocean regions near the equator have become greener than other regions. The conclusions were made on the basis of data collected by scientists in different countries.
The change of colour is due to the increased presence of plankton, which is an ubiquitous marine organism. Heat caused by global warming is considered to be the reason for the changes. Oceans absorb about 90% of the heat trapped by greenhouse gases and when they start warming, the consequences will be severe both on sea and land. Sea levels are already rising because of the melting of glaciers. This leads to fall in oxygen levels in the oceans and the death of fish on a large scale. According to scientists, it is becoming increasingly difficult for the earth to stabilise the amounts of energy entering and leaving its system. This is manifesting itself in different ways, and no place on earth, on land or sea, will be immune to its impact. Everyone will be affected sooner or later in most unforeseen ways.
The scientists who have led the research on the colour of oceans have said: “To actually see it happening for real is not surprising, but frightening. And these changes are consistent with man-induced changes to our climate.” The impact of the change in colour on the marine ecosystems is yet to be studied fully. But it is clear that it will not be beneficial. This is because the oceans contain more life forms than the land, and life on land is crucially dependent on the health of the oceans. Planktons are critical for the existence and survival of the marine food chain. The changes in plankton can change the ability of the ocean to absorb carbon. The greening of the ocean is a red signal. The scientists said in their report: We hope people take this seriously. It’s not only models that are predicting that these changes will happen. We can now see it happening, and the ocean is changing.”