Breaking: 2009 hottest year on record in Southern Hemisphere and tied for second globally

2010 still poised to be hottest year on record despite cool start in parts of Northern Hemisphere

Note: The NASA results are not yet official, but should be Friday. The figure above does not have the December data, but the final figure will look almost identical.

Eli Kintisch at Science Magazine just published, “2009 Hottest Year on Record in Southern Hemisphere.” He quoted NASA mathematician Reto Ruedy of the Goddard Institute for Space Studies on the as-yet-not-released December and yearly data. We’ve all been waiting for NASA’s final report on the year — to see whether 2009 will be the second hottest year on record (see Must-see NASA figures compare 2009 to the two hottest years on record: 2005 and 2007) and whether NASA would make an official prediction that 2010 is likely to be the hottest on record, as the UK’s Met Office has and as Hansen himself did (here).

So I called up Dr. Ruedy, and he said that the data have been processed but won’t be released officially until Friday, as they are awaiting completion of the accompanying report. Here’s the story.

As Science reports:

The United States may be experiencing one of the coldest winters in decades, but things continue to heat up in the Southern Hemisphere. Science has obtained … data from NASA that indicates that 2009 was the hottest year on record south of the Equator. The find adds to multiple lines of evidence showing that the 2000s were the warmest decade in the modern instrumental record.Southern Hemisphere temperatures can serve as a trailing indicator of global warming, says NASA mathematician Reto Ruedy of the Goddard Institute for Space Studies in New York City, given that that part of the globe is mostly water, which warms more slowly and with less variability than land. Ruedy says 2009 temperatures in the Southern Hemisphere were 0.49°C warmer than the period between 1951 and 1980, with an error of +/- 0.05°C.

I asked Ruedy if indeed 2009 was the second hottest year on record and he said yes, and then quickly clarified that, given the error bars on the temperature record (see figure), it’s really best to call it a 3-way tie with 1998 and 2007. In fact, he said, 2005 is “only marginally warmer than” the second hottest years.


This is especially impressive because we’re at “the deepest solar minimum in nearly a century.” The point is, notwithstanding the all-too-effective disinformation campaign of the antiscience crowd, it’s getting hotter — thanks primarily to human emissions — much as climate scientists warned it would:

That makes 2009 the warmest year on record in that hemisphere. That’s significant because the second-warmest year, 1998, saw the most severe recorded instance in the 20th century of El Ni±o, a cyclic warming event in the tropical Pacific. During El Ni±o events, heat is redistributed from deep water to the surface, which raises ocean temperatures and has widespread climatic effects. But last year was an El Ni±o year of medium strength, which Ruedy says might mean that the warmer temperatures also show global, long-term warming as well as the regional trend.

The data come a month after announcements by the National Oceanic and Atmospheric Administration (NOAA) and by the World Meterological Organization that the decade of the 2000s was warmer than the 1990s. (NOAA estimates that the decade was 0.54°C warmer than the 20th century average. The 1990s, by comparison, was 0.36°C warmer by their measure.)

You should be able to read the NASA report Friday here and see their updated dataset here.

In its report last January on “2008 Global Temperatures,” NASA predicted:

Given our expectation of the next El Ni±o beginning in 2009 or 2010, it still seems likely that a new global temperature record will be set within the next 1–2 years, despite the moderate negative effect of the reduced solar irradiance.

Well, they were right about the El Ni±o. It’s true that the El Ni±o is only medium strength, but on the other hand “Central Pacific Ocean surface temperatures are now at their warmest level since the El Ni±o of 1997–98”³ but many models suggest it will last through the spring and possibly the summer (see Met Office: “It is not cold everywhere in the world”). Given the underlying long-term trend of global warming from human emissions, that should be enough to make this year the hottest on record. We’ll find out tomorrow if NASA s willing to make that prediction official.


Finally, while other datasets don’t show 2009 as the second hottest year, notably the UK’s Met Office (and hence WMO), that dataset certainly lowballs the actually landed planetary temperature, as the Met Office itself now admits — see Finally, the truth about the Hadley/CRU data: “The global temperature rise calculated by the Met Office’s HadCRUT record is at the lower end of likely warming.”

Related Posts: