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NASA & NOAA: 2012 Was In Top-10 Warmest Years For Globe On Record

10:12 am in Uncategorized by WeatherDem

According to data released by NASA and NOAA this week, 2012 was the 9th or 10th warmest year (respectively) globally on record.  NASA’s analysis produced the 9th warmest year in its dataset; NOAA recorded the 10th warmest year in its dataset.  The two agencies have slightly different analysis techniques, which in this case resulted in not only different temperature anomaly values but somewhat different rankings as well.

The details:

2012’s global average temperature was +0.56°C (1°F) warmer than the 1951-1980 base period average (1951-1980), according to NASA, as the following graphic shows.  The warmest regions on Earth (by anomaly) were the Arctic and central North America.  The fall months have a +0.68°C temperature anomaly, which was the highest three-month anomaly in 2012 due to the absence of La Niña.  In contrast, Dec-Jan-Feb produced the lowest temperature anomaly of the year because of the preceding La Niña, which was moderate in strength.  And the latest 12-month period (Nov 2011 – Oct 2012) had a +0.53°C temperature anomaly.  This anomaly is likely to grow larger in the first part of 2013 as the early months of 2012 (influenced by La Niña) slide off.  The time series graph in the lower-right quadrant shows NASA’s 12-month running mean temperature index.  The recent downturn (2010 to 2012) shows the effect of the latest La Niña event (see below for more) that ended in early 2012.  During the summer of 2012, ENSO conditions returned to a neutral state.  Therefore, the temperature trace (12-mo running mean) should track upward again as we proceed through 2013.

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Figure 1. Global mean surface temperature anomaly maps and 12-month running mean time series through December 2012 from NASA.

According to NOAA, 2012’s global average temperatures were 0.57°C (1.03°F) above the 20th century mean of 13.9°C (57.0°F).  NOAA’s global temperature anomaly map for 2012 (duplicated below) reinforces the message: high latitudes continue to warm at a faster rate than the mid- or low-latitudes.

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Figure 2. Global temperature anomaly map for 2012 from NOAA.

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NASA & NOAA: July 2012 Was 12th, 4th Warmest On Record

9:49 am in Uncategorized by WeatherDem

According to data released by NASA and NOAA this week, July 2012 was the 12th and 4th warmest July (respectively) globally on record.  NASA’s analysis produced the 12th warmest July in its dataset; NOAA recorded the 4th warmest July in its dataset.  The two agencies have slightly different analysis techniques, which in this case resulted in not only different temperature anomaly values but rather different rankings as well.

The details:

July’s global average temperatures were 0.47°C (0.85°F) above normal (1951-1980), according to NASA, as the following graphic shows.  The warmest regions on Earth coincide with the locations where climate models have been projecting the most warmth to occur for years: high latitudes (especially within the Arctic Circle in July 2012).  The past three months have a +0.56°C temperature anomaly.  And the latest 12-month period (Aug 2011 – Jul 2012) had a +0.50°C temperature anomaly.  The time series graph in the lower-right quadrant shows NASA’s 12-month running mean temperature index.  The recent downturn (post-2010) is largely due to the latest La Niña event (see below for more) that recently ended.  As ENSO conditions return to neutral or even El Niño-like, the temperature trace should track upward again.

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Figure 1. Global mean surface temperature anomaly maps and 12-month running mean time series through July 2012 from NASA.

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NASA & NOAA: June 2012 Was 4th Warmest On Record

7:38 am in Uncategorized by WeatherDem

According to data released by NASA and NOAA this week, June 2012 was the 4th warmest June globally on record.  NASA’s analysis produced the 4th warmest June in its dataset; NOAA recorded the 4th warmest May in its dataset.  The two agencies have slightly different analysis techniques, which actually helps to reinforce the results from each other.

The details:

June’s global average temperatures were 0.56°C (1.01°F) above normal (1951-1980), according to NASA, as the following graphic shows.  The warmest regions on Earth coincide with the locations where climate models have been projecting the most warmth to occur for years: high latitudes (especially within the Arctic Circle in June 2012).  The past three months have a +0.59°C temperature anomaly.  And the latest 12-month period (Jul 2011 – Jun 2012) had a +0.52°C temperature anomaly.  The time series graph in the lower-right quadrant shows NASA’s 12-month running mean temperature index.  The recent downturn (post-2010) is largely due to the latest La Niña event (see below for more) that recently ended.  As ENSO conditions return to normal, the temperature trace should track upward again.

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Figure 1. Global mean surface temperature anomaly maps and 12-month running mean time series through June 2012 from NASA.

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Research: Sea-Level Rise in Response to Warming Climate

7:42 pm in Uncategorized by WeatherDem

From the top, I want to include important context for the research results I am presenting.  This research is based on peak warming of only either 1.5°C or 2°C.  It is my educated opinion that such goals are unrealistic.  Prevention of warming past 2°C is no longer a viable option based on our species’ history of burning carbon-intensive fossil fuels as well as the medium- to long-term future, which doesn’t promise much of a difference.  Furthermore, as I have stated numerous times in the past year, policy discussion would be better served if scientists would conduct research on developments that are much likelier to occur and not the world they want to see (i.e., higher vs. lower emissions scenarios).  That said, this research fulfills an important role in the overall discussion because I think some of the results can be used as a “floor” – conditions are likely to reach higher magnitudes than those found in this and similar papers.

Michiel Schaeffer, William Hare, Stefan Rahmstorf & Martin Vermeer’s Nature paper was published on June 24, 2012.  They examined sea-level rise in response to warming scenarios using a semi-empirical model.  By 2100, global sea-level rise would be ~60cm above the 2000 level if global GHG emissions were zeroed by 2016.  This is an obvious fantasy world, but it provides a useful benchmark for other scenarios the scientists examined.  The reason sea-level rise would continue through the 21st century even if we haled emissions completely in the next 3-4 years is the response of the climate system to the anthropogenic forcing imparted on it through the 20th and early 21st centuries.  If 1.5°C or 2°C warming is not exceeded, global sea-level rise would be 75-80cm above the 2000 level.  The authors also report that unmitigated emissions could result in 100cm rise above 2000 levels.  It is important to note that 20th century sea level rise has been estimated to be ~20cm.  It doesn’t require much thought to realize that the rate of sea-level rise has increased throughout the 20th century and continues to do so in the 21st.  Moreover, it is clear that since we will most likely warm beyond 2°C, the 75-100cm projection can be viewed as a reasonable estimate for a “floor”: actual sea-level rise could be greater than this.

The authors go on to estimate global sea-level rise by 2300.  Since the world won’t end in 2100, nor our civilizations (though they will be forced to adapt to a changing world), projections out to 2300 are useful to gain an understanding of the long-term effects of our actions.  By 2300 a 1.5°C scenario could result in peak sea level at a median estimate of 1.5m above the 2000 level. The 50% probability scenario for 2°C warming would see sea level reaching 2.7m above the 2000 level and still rising at about double the present-day rate.

That last sentence is important to understand because of 2 factors.  The first is the 50% probability descriptor and the second is the extreme difficulty in keeping warming at or below 2°C.  Even if we were to keep warming at or below 2°C, there are realistic scenarios in which sea-level rise exceed 2.7m in the year 2300.  Beyond that, 2°C acts more as a floor in the real world than a ceiling in the fantasy world that continues to garner research focus.  Our historical emissions values were closer to the higher end of the IPCC AR4′s range than the lower – or put another way, 4°C looks likelier to occur by 2100 than 2°C at this point because our emissions more closely resemble the A1B or A2 scenario.  The following graph shows the AR4′s global surface warming projections by scenario.  Note that the A2 scenario didn’t run all the way to the year 2300, but the B1 and A1B scenarios were.  The equilibrium temperature under the A2 scenario is obviously higher than that of the A1B scenario, but left unprojected in previous work.

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7th Day of 100+F Heat In Denver, CO; June 2012 Hottest On Record For CO

2:25 pm in Uncategorized by WeatherDem

It’s official: June 2012 was the hottest June on record in Denver, CO (dating back to 1872) with an average temperature of 75F, 7.6F above normal!

Yesterday’s high of 101F added to the total number of days of 100F+ temperatures: to date, there are now 7.  Last week, there were 5 days in a row of 100F+ heat, matching the all-time record for Denver.  The streak included 2 105F readings, which tied for the all-time hottest temperature recorded for Denver.  There was also a 100F+ reading a few days prior to that streak.  For completeness, I want to point out that the 27th through 30th of June weren’t much cooler: it was 97, 97, 98, and 99 on those four days, so we didn’t miss 100 by much.

Here are a few pictures demonstrating the intensity and extent of the heat that affected not only Denver, but much of the High Plains prior to the impacts east of the Mississippi over the weekend:

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NASA & NOAA: April 2012 Among Top 5 Warmest On Record

8:33 am in Uncategorized by WeatherDem

According to data released by NASA and NOAA this month, April 2012 ranked among the top 5 warmest Aprils on record: NASA recorded the 4th (tied) warmest April in its dataset; NOAA recorded the 5th warmest April in its dataset.  The two agencies have slightly different analysis techniques, which actually helps to reinforce the results from each other.

The details:

April’s global average temperatures were 0.56°C above normal (1951-1980), according to NASA.  The warmest regions on Earth are exactly where climate models have been projecting the most warmth to occur for years: high latitudes (especially within the Arctic Circle in April 2012).  The past three months have a +0.47°C temperature anomaly.  And the latest 12-month period (May 2011 – Apr 2012) had a +0.49°C temperature anomaly.

According to NOAA, April’s global average temperatures were 0.65°C (1.17°F) above the 20th century mean of 13.7°C (56.7°F).  NOAA’s global temperature anomaly map for April reinforces the message: high latitudes continue to warm at a faster rate than the mid- or low-latitudes.  The extreme warmth over Siberia is especially worrisome due to the vast methane reserves locked into the tundra and under the seabed near the region.  Methane is a stronger greenhouse gas than carbon dioxide,which is the leading cause of the warmth we’re now witnessing.  As I discussed in the comments in a recent post, the warming signal from methane likely hasn’t been captured yet since the yearly natural variability and the CO2-caused warming signals are much stronger.  It is likely that we will not detect the the methane signal for many more years.

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