Are we heading for global cooling?

Question

It seems that we have a shift in the PDO phase from warming to cooling.

"Unlike El Niño and La Niña, which may occur every 3 to 7 years and last from 6 to 18 months, the PDO can remain in the same phase for 20 to 30 years. The shift in the PDO can have significant implications for global climate, affecting Pacific and Atlantic hurricane activity, droughts and flooding around the Pacific basin, the productivity of marine ecosystems, and global land temperature patterns. “This multi-year Pacific Decadal Oscillation ‘cool’ trend can intensify La Niña or diminish El Niño impacts around the Pacific basin,” said Bill Patzert, an oceanographer and climatologist at NASA's Jet Propulsion Laboratory, Pasadena, Calif. “The persistence of this large-scale pattern [in 2008] tells us there is much more than an isolated La Niña occurring in the Pacific Ocean.”

According to the climate models will this shift affect temperature predictions? Will this not also affect the positive feedbacks?

Answer 1

i watched discovery channel&they said that we are heading for global freezing which causes by global warming.when the ice on north pole melt it causes several problems to our sea level which will leads to global freezing.sorry if im not helping you but im just telling what i saw&learn from that documentary.

Answer 2

Exactly how would a 20 year weather cycle permanently erase the 1000+ year influence of CO2 once it has been added to the atmosphere?  

As the weather cycle switches back and forth, the underlying warming influence continues (even if it appears to be cancelled out for a few years).  The cycle has no net effect on on the 100 to 1000+ year time scale, but CO2 does continue to have a warming influence on that time scale.  The presence of weather cycle noise may make the climate change hard to see (and difficult for some to understand), but it doesn't remove or slow the underlying warming trend at all.

Here's the actual status of global warming vs. short term weather trends:

http://www.columbia.edu/~jeh1/mailings/2...

Sure. let's assume that the waves in the signal, such as cooling in the 70s, are from the PDO.  Clearly the overall trend is still strongly up, and the 20-30 year wiggles do not stop the 1.5W/m*2 (and growing) warming influence of CO2, or its characteristic of continuing a warming influence for thousands of years.

bob326 -

You clearly understand that the characteristic of the system, namely elevated carbon levels, are what's important, so why sidetrack the discussion to pick nits regarding individual molecules?  Thanks for confirming though that elevated CO2 levels last for at least hundreds of years, which makes 5 year (ENSO) and 20 to 30 (PDO) weather influences irrelevant in the long term.  

Since you're interested, here's the full story:

"To restore the system to a normal level, the excess carbon must be incorporated into carbonate rocks through geologic processes that progress exceedingly slowly. As a result, it is estimated that between 3 and 7% of carbon added to the atmosphere today will still be in the atmosphere after 100,000 years (Archer 2005, Lenton & Britton 2006). This is supported by studies of the Paleocene-Eocene Thermal Maximum, a large naturally occurring release of carbon 55 million years ago that apparently took ~200,000 years to fully return to pre-event conditions (Zachos et al. 2001)."

http://www.globalwarmingart.com/wiki/Ima...

Event a persistence rate of "only" 3% to 7% (!) after 100,000 years, we still march global temperratures upwards indefinitely.  That 100,000 year time scale seems like a long time for us to see what rising temperatures will do to life on the planet.

Tomcat -

If it would be impossible not to cool over the next few decades, why was 2005 the hottest year onn record, and 2007 the second hottest?  When will we start to see the cooling (or are you claiming that a cool February indicates the start of a 30 year trend)?

Even if we were 10 years into a cooling trend (which we're clearly not), what would a temporary 20 or 30 year trend, that we know is about to reverse, mean against the background of a 1000+ year warming influence from CO2?  Wouldn't that simply buy us some time (very temporarily) to react before the major upward spike in temperature hits?

Edit -

As I've pointed out to Tomcat, that might buy us some time, but how in your mind does that affect the overall balance while the warming influence continues?  Since CO2 traps some of the heat that normally would escape the planet, even the cold part of the PDO cycle would still be warmer than natural, so when the warm part of the PDO cycle hit, we'd simply launch from that higher starting point to even higher highs... every PDO cycle.  That appears to be the case in the NASA Goddard 120 year graph, which keep marching upward in the long term, regardless of short term (5 to 20 year) weather cycles.

You haven't explained how that warming pattern could magically stop.  Feedbacks happen because of the underlying influences, not in spite of them.  In other words, feedbacks do not remove the constant warming influence, on a 100,000 year time scale (most prominent for the first 1000 to 1500 years) of increased atmospheric CO2 levels.

Answer 3

Depends on the next solar cycle.  Right now we're between cycles, meaning there are no sunspots.  The last time there was a several year gap between cycles it sent us into a mini ice-age until the cycle started again.

Answer 4

J.S.,

Yes, carbon can spend up to several thousand years in the cycle, but that doesn't mean in the atmosphere. Actual "atmospheric" residence time is from 5 to 200 years, and not all of that is in the atmosphere. Any undergraduate textbook on the carbon cycle would tell you that the residence time calculation is confusing and indeed the concept of residence time is not very useful for a multicomponent system. The average CO2 molecule spends only a few years (2-3), but effective residence time is much longer because of the equilibrium between surface ocean and atmosphere and biosphere. The residence time of a CO2 molecule in the surface ocean is nearly as short as in the atmosphere. So the effective residence time of the combined system is what is important, and that is more on the order of hundreds of years if we are talking about the residence time in the combined surface ocean/atmophere/biosphere, vs. the deep ocean.

Answer 5

We are at least as likely to see a decades-long cooling as we are to return to warming. The current solar cycle, as mentioned by zooba and evans, is #24. It began in January 2008 and so far it is almost non-existent. They had predicted a very robust cycle so it's troubling that it is instead so quiet. Cycle #23 seems to have finally trailed off but there is still almost no sunspot activity. It's still unclear what mechanism links the cycle to Earth temperature, but the last time we had an inactive cycle over a long period of time was during the Maunder Minimum (1645-1715 or so), the coldest period of the Little Ice Age. That would effect the PDO but I doubt it's behind it's current activity, we're probably a few years from experiencing the results of an inactive solar cycle.

Answer 6

Your source also says:

[quote]

Natural, large-scale climate patterns like the PDO and El Niño-La Niña are superimposed on global warming caused by increasing concentrations of greenhouse gases and landscape changes like deforestation. ... “These natural climate phenomena can sometimes hide global warming caused by human activities. Or they can have the opposite effect of accentuating it.”

[end quote]

The ocean/atmosphere must be thought of as a system. It doesn't produce heat nor does it destroy heat it merely shifts it around (basic physics).  The source of the excess heat which is slowing heating up the entire ocean/atmospheric system is excess energy from the sun trapped on our planet.  And with atmospheric CO2 levels high for centuries (CO2 remains there for a long time) 20 - 30 year ocean or wind circulation changes are only noise, they don't change the energy balance equation.

Answer 7

and for those that dont care to follow the links, the next paragraph of the piece quoted in the question is;

"Natural, large-scale climate patterns like the PDO and El Niño-La Niña are superimposed on global warming caused by increasing concentrations of greenhouse gases and landscape changes like deforestation. According to Josh Willis, JPL oceanographer and climate scientist, “These natural climate phenomena can sometimes hide global warming caused by human activities. Or they can have the opposite effect of accentuating it.”

Answer 8

Don't forget the unusually quiet solar cycle 24!  

A panel was formed to predict the next cycle in 2007.  The panel was split almost evenly over high and low estimates.  March 2008 was the agreed upon "likely" solar minimum (where solar cycle 23 ends and solar cycle 24 begins).  When asked what would sway opinion to the other side, both sides pointed to activity in relation to this past month as the deciding factor.  

Based upon these statements, and sunspot measurements to date, the panel would be leaning to a weak solar cycle 24 (which would cause a cooler globe for the next 11 years or so).  The next 5 months will be extremely telling on where we're heading on a global climate scale.

http://www.swpc.noaa.gov/SolarCycle/SC24...

Answer 9

but a GW "expert" said the sun has nothing to do with our climate... thus no impact on global warming...(hahahaha)

While local, or oceanic and atmospheric, weather related phenomena have an impact on climate as much as they are affected by climate...the sun is chiefly responsible for our climatic changes  and the last I heard the sun output indicated that we were on a cooling trend.

Answer 10

All current scientific evidence seems to indicate that we may have already reached our peak global temperatures, at least for the time being, since there has been no increase in global temperatures since the turn of the century.

Some people claim that the temperatures have dropped during the last 10 years.

I personally don't accept any information at 'face value' just because I would like it to be true or not.

While I hope that we have not yet reached our peak in global temperatures, I also know that we will have to accept whatever 'Mother Nature' throws in our direction.

The PDO seems to be another possible explanation for some of the earth's changes, but it is only part of the whole picture(my opinion).

I still have a bit of a problem with the term 'positive feedback' as this term has been so misused and abused in the past, and is mainly used in 'computer modeling', which has nothing to do with science.

Answer 11

Yes we are, it would be impossible for the world not to cool over the next 30 years. One look at the most contaminated temperature record clearly shows the PDO's 25- 30 year step influence on climate.

http://data.giss.nasa.gov/gistemp/graphs...

The last 30 years of the PDO warm phase, also has a very well known and documented warm bias in the GISS data associated with urbanization effects. One look at the lower atmosphere in the tropics measured by satellites, and there is no evidence of any alarming warming associated with anything other than the PDO warm phase over the last 30 years. The global warming theory predicts the tropical atmosphere should warm at a faster rate than any other point on the planet, it has not.

http://www.ssmi.com/rss_research/climate...

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