MusicScienceGuy

Global Warming - The "Blanket" analogy

Recently a call went forth for super-brief "elevator pitches" about global warming. I am no expert, but have followed the science, events and drama for more than 20 years. Here goes my stab at slimming the topic to the core:

 

  Earth's Blanket back then

 The Earth has an invisible secret: we are covered with a very effective, very warming blanket. This blanket is our atmosphere, and it contains a crucial ingredient; thin heat-trapping gases. These so-called “greenhouse” gases are dilute; just 1 part per thousand. Without this insulation warming us the Earth would average a chilly -18 °C. The blanket warms our planet up by an amazing 33 °C.

Here’s the problem: we are steadily making the blanket much thicker. Compared to a century or so ago, our air now contains over twice (~110% more *) the insulating gases. With steadily increasing insulation over us, the Earth is inevitably heating up, and at an increasing pace.  

 

 

Now twice the thickness ...

 Luckily, the added blanket or two won't double-up the heating by another 33 °C: we'd all be pretty sunk if the Earth were heading for average temperatures above +40 °C. With blankets one naturally gets diminishing returns; the first one gives the most warming, the second one, not so much. Climate scientists have carefully measured, calculated and checked, but blankets, even earth-sized ones, are basically simple. With the gasses added to date they can’t see how Earth can avoid warming by at least 2 - 3 °C. Worse, when we hit blanket number 3 (or 4) Earth's average warming will inevitably pass 6 °C.

So warming is happening (see the chart below). The only real questions are: how long will it take, and what will the peak be?  See my following posts. 

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Temperature data from four international science institutions. All show rapid warming in the past few decades. The 10 warmest years in the 134-year record all have occurred since 1998, with 2010,  2005 and 2015 ranking as the warmest years on record. The coldest was 1912.

Credit: NASA.  http://climate.nasa.gov/faq/ 

And that is my "elevator pitch".  I hope you find it useful -

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* Source: Carbon Dioxide Information Analysis Center (CDIAC), posting updated Feb 2014. Totaling the "Increased radiative forcing" column gave an eyebrow-lifting 3.28 W/m² . Of this, 1.88 is due to CO²,  1.40W/m² is due to gases other than CO²: other gases boost the CO2 blanket by 74%.
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What the heck is the "greenhouse effect"?

Is the "Greenhouse Effect" a dated term?

 Here's a question for you:

The term "greenhouse effect" is slightly, in some ways, more accurate.

But is it confusing? A greenhouse is abstract, while everyone understands blankets. 

Let me know what you think.

 

 Updated April 27, 2015

 

 

3.28

Global Warming - Where's the heat?

Just how big is the threat?

Holding back?

There's a common theme in Hollywood movies, where the heroes battle with some monster and vanquish it. The action pauses, and they catch their breaths after putting out their utmost, an utmost that was barely enough.

The most thoughtful member of the band looks up, clears his or her throat a bit deferentially, and says "You know, it's weird, but my new measurements and calculations show that the enemy will recover and is still growing." The rest of the tired troupe blink and the youngest whispers with shaking breath "You mean it is going to get bigger?"  The thoughtful one pauses, thinks carefully, and says "much, much bigger." 

Not a movie script?

Real life does not usually resemble a Hollywood movie, but with global warming we might just be following the above script. Why? Partly because scientists, while thoughtful, are notoriously slow and cautious, and partly because climate scientists never want to appear alarmist. As a rule, a scientific prediction either nails it, or understates.

   Lately there has grown up a curious practice of climate-science skepticism. If a predicted climate change is "probably X" and only half X happens, the skeptics say "See! X didn't happen; ergo there is no climate change". Other times, X (for example: record droughts) happen, but are dismissed because Y (for example: snow in Boston) also happened. 

Yet climate scientists base their temperature estimates on very solid laws of nature, and the only real wiggle-room those laws give is in timing and location.  So, contrary to the skeptics' view, seeing just half X is not a good sign; global warming may just have been holding back or hiding a bit.

 

In light of new measurements and calculations

Earth's Energy Imbalance; Hansen et al.

New climate information is coming in all the time. We now know, courtesy of 3,847 new Argos ocean probes, first that a huge amount of "greenhouse effect" heat is being loaded into the deep sea, and second,  that a mere 4% of the newly trapped heat went into warming the land from 2005 through 2010. See the chart to the right. 

This is fascinating yet sobering:  the record high global temperatures seen in the last decade were caused by less than one twentieth of the incoming extra energy.  Climate energy flows are rather large.

Note that these are flows.  Flows are subject to variation and change. When they are changing they will not always be steady and do not have to balance ... for a while. 

 

 Energy does not disappear, but it can hide

Question to ponder

 
Despite Anthony Watts' proclamations in the WattsUpWithThat blog, energy is relentless conserved,  even if it's not for the moment on our doorsteps.

For years climate researchers very strongly suspected that the extra trapped heat was going into the ocean, but until the Argos probes were deployed, they could not prove it.

However, there is no guarantee that Earth's new heat won't decide to go somewhere else. Or that new sources of heat won't appear.

 

 

In Hollywood movie terms: if the monster gave up early, you can rest assured sure he/she will be back ... with his mom.