Weather vs climate

It’s been somewhat chilly in the USA in recent months, leading some people who are trying to come to terms with the fact that climate change is real to start thinking perhaps it’s a crock.

In South Australia a few weeks back, we had some heavy rains, inciting some to say that the drought was about to break, global warming related drought was over-hyped; etc. etc. etc.

The heavy rains lasted a day or two… but we’ve had next to no rain since. The rain came down, and much of it ran off due to the hard crust formed on the soil through the drought. I think in the future, we’ll be seeing less rain periods and more major rain events – but with less total annual rainfall. It’s not the best way to get moisture into the soil, in fact it can do more harm than good sometimes through flash flooding erosion.

It’s important not to confuse weather with climate. Weather is the set of meteorological conditions happening within a short space of time. Climate is the meteorological conditions averaged over a long period. You may see a spike or trough in temperatures over a few weeks or months; but how does it stack up when averaged over a year? I think you’ll find come the end of 2007, most average temperatures around the world would have risen…. again.

There is another wild card in the pack in relation to global warming induced climate change. Some scientists believe it could actually make some areas of the world even colder; particularly in the northern hemisphere.

The northern hemisphere’s climate is pretty much controlled by the Gulf Stream – a massive current of warm water in the Atlantic Ocean. This conveyor belt moves heat from the equator region to the Arctic; warming the surrounding countries as it passes. Warm water rises and cold water sinks; and it’s this warming and cooling that drives the Gulf Stream current. Heavily saline water also sinks faster than less saline water.

Increased meltwater from glaciers, directly linked to global warming, decreases salinity as it is fresh water. Less saline water sinks more slowly, therefore the push/pull effect of the current is weakened. The slower the water moves whilst in the upper northern hemisphere, the colder it gets and it’s the temperature of that water that can have a lowering effect on the temperature of countries in the Northern Hemisphere.

The disturbing thing is that a weakening in the Gulf Stream has been detected in recent years.

So, just because you may be experiencing colder temperatures and more wet or snowy weather than usual, it doesn’t mean that global warming induced climate change doesn’t exist – it could be just a temporary weather pattern; or still directly linked to the warming of the planet.

Time will tell. Regardless of what some ignorant politicians say, the effects of global warming won’t be fun for much of humanity.