A Warming World

The Oceans are Warming

Since the 1950s, when routine atmospheric CO2 measurements began, scientists have been concerned about the increasing concentrations of CO2 brought about by human activities and the resulting warming effect this has on the planet. The problem, of course, is that the carbon locked up in the oil and coal fields, the result of the burial of tropical forests over tens of millions of years, is very likely to be returned to the atmosphere in a few centuries.

By the end of this century, atmospheric CO2 concentrations are likely to reach 600 ppm, not present on the Earth for perhaps 10 million years. Although the planet has naturally warmed and cooled over long periods of time, scientists are concerned that human activity has, to a great extent, induced recent global warming trends.

The rapid rise in temperature during the latter half of the twentieth century is alarming and, should it continue, cause for concern. As the planet has warmed, so has the ocean, contributing to sea level rise, thinning of arctic ice, dramatic calving of ice-shelves in Greenland and Antarctica, shifts in precipitation patterns and hence ocean salinity patterns, and changes to the lifecycle and habitat of many ocean species.

Abrupt Change?

Global warming could occur gradually, over the course of a few centuries. However, some scientists speculate that the climate might be pushed into a more erratic state that could trigger abrupt change—and that many living things, including humans, could find it difficult to adapt.

The possibility of imminent abrupt climate change is small. As far as we know, such an occurrence is even less likely during warm periods in Earth’s history, such as the present. Still, the potential for such an event must be taken very seriously because the impacts on the environment and humanity would be so great.

The paleorecord suggests that such events have happened very rapidly in the past (on timescales as short as a decade). We simply do not know if and when an abrupt climate shift will occur and, if it does, the extent to which human activities will have played a role.

As the climate changes, researchers at MIT and WHOI are observing the effects of those changes on the ocean and the role the oceans play in them. We are also helping to build the observing systems and models required to make projections about how the oceans may evolve, in all their physical, chemical, and biological aspects.