Experts are predicting that the earth’s temperature will increase by 4.8 degrees Fahrenheit by the end of this century. This dramatic change will impact many aspects of the environment, including the colour of our oceans. Warming on this scale will cause an increase in the growth of plankton which, in turn, will intensify the blue and green tones of water. Oceans throughout the world that are noticeably blue, such as those located between the Tropics of Cancer and Capricorn, will become even bluer. In the case of nutrient-rich green waters, like the oceans at the North and South Poles, deeper greens will emerge. Although humans may not be able to detect these colour fluctations, the transformation will negatively impact the food systems currently supported by these large bodies of water. It’s another example of how bright colours can act as a warning signal.