A scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die and a new generation grows up that is familiar with it.
I remember doing a high school experiment in one of my science classes. It had a big impact on me because I can’t say that I remember any other experiment as well. But it taught me an important scientific principle that I think few people appreciate.
The experiment had to do with the rather lofty-named concepts known as “Latent Heat of Fusion” and “Latent Heat of Vaporization.” All we did was took some ice, put it in a beaker, put the beaker on a hot plate, and put a thermometer inside the beaker to record the temperature. Since the ice started at a temperature below freezing, we watched the temperature slowly climb, then watched the ice melt, then continued to watch the temperature climb, then watched the water boil and evaporate, and then finally watched the temperature of the steam climb. Doesn’t sound all that exciting, I know.
But here’s the interesting observation that people don’t usually realize until they see it for themselves. When the ice was melting, the temperature stayed the same for a few minutes before starting to climb again once the ice was all melted. Likewise, when the water started to boil, the temperature remained at the boiling point until it was finally all converted to steam. After that, the temperature rose once again as the steam got hotter.
It turns out that as heat is added to something, that object heats up and its temperature climbs. But when it goes from one state to another—such as a solid to a liquid, or a liquid to a gas—then it takes heat to change that state, but during the phase transition, the temperature doesn’t climb because the heat energy is being used for the transition itself. That’s what’s referred to as the latent heat of fusion (i.e. melting) and the latent heat of vaporization (or boiling off and evaporating).
So what does this have to do global warming? Well, I’m always impressed that people forget that global refers to the entire planet. Some people overcome the hurdle of thinking only about their own backyard so that they understand that one hot summer in North America doesn’t prove global warming. (But ten hot summers in a row might.)
But another hurdle people have to think about is that our planet is made up of more than just land. In fact, nearly three-quarters is water, and of course there’s the atmosphere as well. Those three components—land, water and air—all absorb heat and all are affected by global warming.
So when some skeptics quibble about land surface temperatures and whether or not they confirm that global warming is indeed really happening, sometimes they forget that there’s an ocean (and an atmosphere) that’s warming as well. Studies have shown that the Earth’s heat content has been accumulating (i.e. a net gain of heat rather than a balanced equilibrium) at a rate of 190,260 gigawatts, with the vast majority of that energy going into our oceans for the simple reason that the oceans make up most of the planet.
Remember: Marty McFly needed 1.21 gigawatts to get “Back to the Future,” and that amount is actually more than most nuclear power generators produce today. That’s why he needed a bolt of lightning in 1955 to accomplish his task. 190,000 nuclear power generators dumping all of their heat into our oceans: that’s effectively what’s happening on our beloved planet.
Over the last fifty years, our oceans have been rising in temperature by about 0.1 degree Celsius per decade. It’s an even faster rise in the Southern Ocean near Antarctica where it’s climbing about 0.17 degrees Celsius per decade. (That’s because the poles are more sensitive to global warming than the rest of the planet.)
That’s a lot of heat to absorb to raise the temperatures of all of our oceans. And when you take into account that some of the absorbed heat on the planet is causing ice to melt at both poles as well as many of Earth’s glaciers—and that heat won’t cause temperature to rise as my old high school experiment helped to demonstrate—well, that’s a huge energy imbalance our planet is undergoing.
We’re not helping this problem. We’re hurting it. As we continue to dump greenhouse gases (more than 30 billion tonnes of carbon dioxide a year, not to mention other gases such as methane), all we’re doing is adding more blankets of insulation to our atmosphere. We’re going to worsen this energy imbalance in the years to come.
As far as I’m concerned, it always comes back to understanding the science. If the adult population alive today can’t get their heads around some of these concepts, we can at least make sure we educate our children so they can get it right where we failed.