Idaho Oct-Mar Temperature Anomalies (degrees F from 1970-2000 normal)

The mild winter in the inland Northwest during 2010, particularly since Jan 1 has been remarkable, with several stations recording their warmest Jan-Mar minimum temperatures on record, while for long-running stations the infamous winter of 1934 stands out as being unwinterlike.  However, the anomalous warmth this year is very much in line with GCM based predictions for a “normal” winter in the mid-21st century.  A nice commentary on this and the impetus for this post:

Lifted from the blog of Dr. Cliff Mass (UW, Atmospheric Science)

• The combined global land and ocean average surface temperature for March 2010 was the warmest on record at 13.5°C (56.3°F), which is 0.77°C (1.39°F) above the 20^th century average of 12.7°C (54.9°F).

• For the year-to-date (January-March) period, climatic extremes were seen the Northeast where Maine, Vermont and New Hampshire each experienced their warmest such period. Other states that were abnormally warm were Washington (3^rd warmest), Connecticut (7^th warmest), Rhode Island and New York (8^th warmest), Massachusetts and Michigan (9^th warmest), and Oregon (10^th warmest).
• The unrelenting cool pattern during the winter season spilled into the three-month period as several states were below normal. It was Florida’s coldest ever, Louisiana’s second coldest, and the third coldest for Mississippi and Alabama. Georgia, South Carolina, and Texas also experienced a January-March period that ranked among their five coolest.
• According to the Canadian Ice Service, mid-March ice coverage over the Great Lakes was at a record low – only 3.5 percent of the lakes’ surface. The normal ice extent for the period is roughly 31 percent of the lakes’ surface. Records go back to 1973.

Sources:

http://www.ncdc.noaa.gov/sotc/?report=global&year=2010&month=3&submitted=Get+Report

http://www.ncdc.noaa.gov/sotc/?report=national

Sheep Albedo Feedback in Action

http://www.realclimate.org/index.php/archives/2007/04/the-sheep-albedo-feedbacki/

A new culprit for the increase in global mean temperatures:  bahhhh

Annual Snowfall at Reagan National Airport

Apparently the CSI series has really branched out beyond run-of-the-mill cases involving espionage or murder. The case at hand today involves the record snowfall received this winter across parts of the East Coast (see, snowmageddon, snopacalypse).  This week the team determines whether this can be linked to anthropogenic fingerprint, or just natural variability.

http://www.climatewatch.noaa.gov/2010/articles/forensic-meteorology-solves-the-mystery-of-record-snows

Yes, it’s early in 2010, and yes it has been rather chilly in parts of the globe.  But, if we take a global view of the matter and do our best to take the global temperature using brightness temperatures from microwave soundings that provide nearly full coverage of the globe, 2010 is off to a hot start.  There are caveats associated with all measurements; however, as it stands right now 2010 has clocked in with the warmest single day in January, February, and now March for the period of record available (1998-present) – generally regarded as the warmest decade in recent memory.  Absolutely, the strong El Nino which has begun dissipating it likely the primary instigator on the interannual timescale, helping bump temperature for much of the latter part of 2009.  El Nino’s influence on global temperature has been estimated for the historically significant 97-98 event at close to +0.25C, with the bulk of the influence being in late winter through 2010.  This lagged response can partially explain the relatively cool period in 2008 due to El Nino’s sister, and might be able to allow 2010 to take the gold as the warmest year on record.  Note that although the El Nino events of 82-83 and 97-98 were much stronger than this years rendition, it is still pretty warm.  Unexplained variance or anthropogenic forcing: you make the call.

BE IT FURTHER RESOLVED, that the Legislature urges that all instruction on the theory of global warming be appropriate to the age and academic development of the student and to the prevailing classroom circumstances.

http://www.foreignpolicy.com/articles/2010/02/25/the_fp_guide_to_climate_skeptics?page=0,0

On Feb. 24, Andrew Revkin from Dot Earth posted a few alterations to the way the IPCC and other climate change institutions will be handling data and the writing of the reports.  The World Meteorological Organization from Britain’s climate and weather agency proposed to provide a transparent set of terrestrial temperature records.  In addition, the IPCC authors are attempting to be more inclusive of critical opinions in the next round of reports; however, Revkin reports that Roger A. Pielke Jr., a critic of climate change from University of Colorado, was not included on the next discussion of managing risks from climate extremes even though his publication record is extensive.  It seems that some of the negative aspects we have discussed in class; lack of transparency, better writing in the reports, and inclusion of climate change skeptics are being addressed, but we shall see how much change actually occurs.

planet was substantially warmer than present (close to 2C in a global sense) despite the fact that GHG concentrations were within the historical range of variability of glacial-interglacial cycles (180-280 ppm).  This fact has been used incessantly to make the claim that “CO2 was not important during previous warm periods”. Statements like these have been used to indirectly justifying ignoring the theory of anthropogenic climate change.

So, what gives?  Can we explain why the planet was warmer 125 kya ago despite the fact that radiative forcing from GHG would have been substantially lower than today? Is the last interglacial a decent analog to present day climate? Let’s take a look at the evidence.

1. Continental plates were not significantly different from today, so those are largely ruled out.

2. Factors associated with aerosols and volcanic activity have very low confidence and are not suggested to have contributed.

3. We have fairly strong confidence and knowledge of orbital parameters and can state that phasing of the three Milankovitch moments were quite different during the last IG than present.

Let’s examine #3 in more detail. Results suggest that eccentricity (the shape of the orbit) was less circular (more eccentric) during the last IG (see the green line below) and the seasonality of inso

lation (through precession and obliquity) was significantly higher (red line).  This allowed for summer insolation at high-latitudes (65N, black line) to be significantly greater than today leading to significant melt and negative mass balance of the cryosphere, invoking a positive ice-albedo feedback to drive warmer global temperatures.  It is important to note here that these changes are not simply due to the amount of energy incident to the planet increasing or decreasing, but instead the means through which it is distributed latitudinally and seasonally (and invoking feedback processes).

Orbital parameters alone suggest that the globe should be going through a slow cooldown over the last 6kya in the absence of other forcing mechanisms.  Why? Today perihelion (when the Earth is closest to the sun, hence largest insolation potential) occurs during in January, and vice-versa for aphelion. This effectively muddles the seasonality of insolation at northern latitudes (not as much insolation during summer, more in winter). As ice-sheets and land-ice is most likely to form in the NH due to the abundance of high-latitude landmass, the present parameters are not conducive for the retreat of cryospheric content in the NH.Flip back to 10kya when perihelion occurred during NH summer and you would find a time where conditions were more amenable for melt.

This brings us back to the present climate where we know that orbital parameters are not “stellar” for warming. Furthermore, orbital projections are not suggestive of conditions conducive to warming in the pipeline (see the right side of the graph below) over the next 1000yrs.  So while GHG forcing may not have been THAT important 125kya ago; it just might be today.

Note that minimum temperatures look very different than the TMAX time series shown below: http://www.wrcc.dri.edu/monitor/cal-mon/frames_version.html