Oceans cover more of the planet than anything else. So
it makes sense that we need to know what's happening to them to
understand how humans are changing the climate.
If you follow climate science, you'd be forgiven for
being a little confused recently by different news reports
suggesting the oceans are warming,
cooling or doing
nothing at all.
So are the oceans hotting up or aren't they? And how
does what happens beneath the waves influence what we feel up here
on earth's surface? Here's our top to bottom look at the oceans and
More heat in, less heat out
Scientists have known for centuries that greenhouse
gases in the atmosphere, such as carbon dioxide and methane, trap
heat and warm the planet. This is known as the
Scientists use satellite
measurements to monitor how much of the sun's energy
enters earth's atmosphere. A different set of measurements tells
them how much finds its
way out again.
The difference between
those numbers is increasing, which means the earth is
trapping more heat than it used to. And that means the
must be warming.
A hiatus in surface warming
An interesting question is why temperatures at earth's surface -
that's the air above land and the very top of the ocean - don't
always reflect what's happening to the planet as a whole.
Over the last 15 years or so, surface temperatures
much slower than in previous
decades, even though we're emitting greenhouse
faster than we were before.
This is what's become known as the "hiatus",
"slowdown" or even "pause" in surface warming.
This raises an obvious question. If earth is
gaining heat but the surface isn't warming very much,
where is the heat going instead?
Where does the heat go?