Since nearly everyone has just had a holiday this week I thought I would give weather school a holiday and instead touch on a weather item that, to be frank, has gotten me a little upset over the last month or so.
Maybe it’s my fault for listening to some of these syndicated radio talk shows, but over the last couple of months I have heard more and more bad weather science being touted on these shows as definitive truths on why global warming is a crock of crap. I then find these half-truths and bad science surfacing in everyday conversations and I just can’t help but feel my blood pressure rising. That’s not because I am a diehard believer in human-induced global warming, but rather because I hate it when people who are not experts in an area of study decide to do a little bit of research and then proclaim to the world that everything is really quite simple and their point of view is the correct one and all others are idiots. Heck, I would be just as upset if the opposite was happening.
So, just what is it that’s got me all riled up? It’s the talk about global ice amounts and how the data now show that we have more global ice cover than we have seen since satellite records began in 1979. This statement by itself is true (however, only when comparing winter ice cover) and I have no problem with it. What I have a problem with is the linking of this piece of information with the idea that this proves beyond a shadow of a doubt that there has not been any global warming.
WINTER ICE PACKS
On the surface, the linking of these two things kind of makes sense; after all, how can the total amount of ice on Earth remain the same or even increase a little bit, if the Earth is warming up? To understand the problem with this, you need to understand where this statistic about ice comes from. The total ice cover for the Earth is the combination of the Arctic and Antarctic ice packs. Over the last 10 or so years, the Arctic ice pack has undergone dramatic declines during the summer, but during the winter the amount of ice has remained about the same (with some small decreases) as the cold weather allows the ice to grow back. The Antarctic ice pack has been either holding its own or actually increasing in size during the winter months. So the small increases in the Antarctic winter ice pack, combined with only a small decline or no decline in the Arctic winter ice pack, would mean that during this period, the global ice cover is greater – but not during the summer.
Now, to simply combine these two vastly different areas together, along with the timings of when the measurements are being made, and then make a blanket statement that Earth’s ice cover is not changing or is getting larger and therefore global warming is not occurring is just wrong – it is bad science. To quote Jeff Masters, the founder of the weather underground, “Cleverly quoting irrelevant facts about global wintertime sea ice data to hide the summertime loss of Arctic sea ice is a tremendous disservice. It’s like hiding the potential impact of a major hurricane in a one-week forecast by saying ‘The average peak wind speed for the next seven days will be 17 mph,’ and neglecting to mention that the wind will be calm six of those days, but 120 mph on the other day.”
POLAR WEATHER PATTERNS
The fact that the Arctic is losing large amounts of sea ice during the summer months will likely have a significant impact on the global climate system as more energy is absorbed into the Arctic Sea. But why are we seeing the Arctic melt while the Antarctic stays the same or even sees an increase in ice cover?
To understand this, we need to realize that our two polar regions, while appearing to be very similar, are actually quite different. The Arctic is an ocean surrounded by huge land masses, while the Antarctic is a huge land mass surrounded by oceans. These immense differences result in a much different weather pattern in each area. Around the Antarctic there is a very strong band of westerly winds that blow around the pole. This circumpolar vortex extends from the surface to the stratosphere, and can attain very high wind speeds, thanks to the absence of large land masses to slow it down. This vortex tends to isolate Antarctica from the rest of the globe, keeping global warming from influencing Antarctica’s weather, and allowing the surface to cool. These winds have been increasing in speeds over the last 20 to 30 years.
Interestingly enough these winds are caused, as we learned earlier this year, by a difference in temperature between the polar region and the subtropical regions. The question is: Is the current strengthening of this band of winds the result of some natural cycle, or have the temperatures increased over the subtropical region? Something to think about.
If we looked at Antarctica we would see that the Antarctic Peninsula sticks out past this band of westerly winds and is therefore not “protected” from any potential global warming. Interestingly, the climate records from this region show that temperatures have warmed significantly over the last 20 to 30 years.
I see I have run out of room for this week. Next week I will continue with the second-most annoying weather comment: that is, how can we be experiencing record-cold temperatures if the planet is warming up?