"(Solar minimum) has counteracted some of the warming action of greenhouse gases from 2002-2008."

[joshcryer]

SOLAR MINIMUM VS. GLOBAL WARMING: From 2002 to 2008, decreasing solar irradiance has countered much anthropogenic warming of Earth's surface. That's the conclusion of researchers Judith Lean (NRL) and David Rind (NASA/GISS), who have just published a new analysis of global temperatures in the Geophysical Research Letters. Lean and Rind considered four drivers of climate change: solar activity, volcanic eruptions, ENSO (El Nino), and the accumulation of greenhouse gases. The following plot shows how much each has contributed to the changing temperature of Earth's surface since 1980:



Volcanic aerosols are a source of cooling; ENSO and greenhouse gases cause heating; the solar cycle can go either way. When added together, these factors can account for 76% of the variance in Earth's surface temperature over the past ~30 years, according to the analysis of Lean and Rind.

Several aspects of their model attract attention: "The warmest year on record, 1998, coincides with the 'super-El Nino' of 1997-98," points out Lean. "The ESNO is capable of producing significant spikes in the temperature record." Solar minimum has the opposite effect: "A 0.1% decrease in the sun's irradiance has counteracted some of the warming action of greenhouse gases from 2002 - 2008," she notes. "This is the reason for the well-known 'flat' temperature trend of recent years."

What's next? Ultimately, the authors say, temperatures will begin rising again as greenhouse gases accumulate and solar activity resumes with the coming of the next solar cycle. Of couse, the solar cycle could be out of whack ( http://science.nasa.gov/headlines/y2009/03sep_sunspots.htm ); if solar minimum deepens and persists, no one is certain what will happen. Lean and Rind reveal their predictions for the future here ( http://www.agu.org/pubs/crossref/2009/2009GL038932.shtml ).

http://spaceweather.com/archive.php?view=1&day=05&month=09&year=2009

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Being a long time space observer, the solar minimum has been something of deep conversation with other space fans I know. We keep expecting it to end, but there's so far no end in sight. Whenever one tiny sunspot occurs my email lights up. Not so in quite some time.

Could we be in for some serious heating when (if?) this solar minimum ends?

[Richard D]

1. Considering Antarctica . . .

. . . is at its highest temperature in 2K years we are probably in for some serious shit meet fan when the sun starts the cycle towards a solar maximum.

[joshcryer]

5. If the trends continue the way they are we may have to petition IPCC to stop being so conservative.

They will have to be frank in AR5.

[Barrett808]

2. It's funny that the actual solar forcing is the opposite of what contrarians claim

It just gets worse and worse for them.

[bhikkhu]

3. An ENSO question

The article lists ENSO as one of the four drivers of climate change. In my understanding, ENSO is simply an acronym for the El Nino/La Nina variables in ocean currents, which are not so much causes as they are results. You can say that they affect local surface temperature readings in that they affect the distribution of weather conditions and so forth, but in no way do ocean currents globally create or destroy heat energy...correct?

[joshcryer]

4. That's exactly it, however, they do *store* energy, which in the event of a significant release...

...could be quite interesting. We are just getting out of a significant La Nina, similar to the one in 1998. The coming El Nino may look very similar to 1998. I expect record temperatures in 2010-2011. Here's hoping solar intensity doesn't kick back up until after then!

[Barrett808]

7. My understanding is that an El Nino does radiate more heat to space

And so can "delay," but not avert, the rising global average temperature trend.

[Dead_Parrot]

6. We stopped generating energy in 2002 so there's no more waste heat

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