As you probably know by now, I have a tendency to blog ad nauseum about global warming and the Arctic Ocean - I admit it, I find that to be an intriguing topic. I'll bet, though, that many of you may be wondering what's been happening with Earth's climate in a broader sense.
In a word: warming! In lots of words? Hang on....
First of all, Robert A. Heinlein probably said it best when he said, "Climate is what you expect, weather is what you get."
Here's a glimpse of recent weather in the USA...
- 2.1 million acres burned in wildfires
- 113 million people under extreme heat advisories
- 2/3 of the country experiencing droughts
- Regional flooding in MN and FL
- A derecho (a straight-line storm that was 5x more power than a normal thunderstorm) blowing from Chicago to Washington DC
- 3,215 new daily high temperature records
When we look back a bit farther, that is, since January 2012, we have experienced over 40,000 new daily high temperature records across the USA. Yow! Historically both high and low temperature records were set at about a one to one ratio. But Borenstein (see the source below) reports that between 2000-2010 we observed two new high temp records for each low temp record, and that so far during 2012 we are seeing seven new high temp records for every new low temp record. And, scientific climate models also indicate that by the middle of the century we may see a ration of twenty to one!!!
(Source: "Climate Change: US Heat Waves, Wildfires, and Flooding Are 'What Global Warming Looks Like', by Seth Borenstein, AP 03:04am 07/03/12).
As this article mentions, it is extremely difficult to tie a particular weather event directly to climate change, because weather is twitchy...it's all over the place. One thing that can safely be said, however, is that scientists have predicted these kinds of events to become more likely to occur as climate change proceeds in its warming trend.
In order to see what's going on with climate we need larger sets of observations, ideally at least 30 years' worth in order to see whether any observable trends are emerging.
The following data are from the National Oceanographic and Atmospheric Administration (NOAA) and the National Climactic Data Center (NCDC) 21st Annual State of the Climate Report. (FYI, this report is peer-reviewed and includes work from scientists from 45 countries.)
- The first important finding is that the Earth is still getting warmer.
- The second important finding is that CO2, an important greenhouse gas, is still on the rise in Earth's atmosphere.
- About now some people ask, if CO2 levels are rising, why isn't the Earth heating faster? One of the main reasons is because much of the excess energy is being absorbed by the ocean. This can happen because water has to absorb a LOT of energy before its temperature increases. If it wasn't for the ocean's huge heat capacity, we'd probably already be experiencing runaway warming, not just the gradual warming we see today.
- Some people are convinced that the current, observed warming trend is the result of increasing solar output. This is not the case. If you look at the graph below you'll see solar output fluctuating slightly up and down, but there is no long-term trend increasing solar output, so that just doesn't match up with warming we see.
- Glaciers are melting
- Total greenhouse gas concentrations are increasing
- Next, sea level is continuing its slow, but steady rise
- Arctic sea ice is melting...its actually melting at about 2x the historical average at the moment.
- And there is less spring snow cover than in years past.
In addition, northern latitudes are getting warmer and having longer growing seasons.
When you add all of these things together, what do you get? All of the data together support only one main conclusion...global warming.
It's real, and it's happening. Now what are we going to do about it?