My First Election

I don’t intend to talk much about politics on this blog, but in this case I’ll make an exception. Australia will have its 43rd federal election on the 21st, and I am a first-time voter. In a follow-up post either later today or tomorrow, I’ll get into a bit of politics — and given the subject matter of my blog, I’ll mostly be talking about climate policy — but for now, a bit of background about, and analysis of, the Australian electoral system.

Voting is compulsory, though it’s a secret ballot so voters are free to “vote informally” by leaving their ballot paper blank or incorrectly filled in. There are two houses of Parliament: the lower house is called the House of Representatives, and the upper house is the Senate. The House has 150 members, who serve three-year terms and are elected from single-member electorates. Each electorate is supposed to contain more or less the same number of voters (though the rules are complicated, and in practice the number can vary from around 60,000 to around 120,000).

In House of Representatives elections, Australia uses a preferential voting system called instant-runoff voting. Voters must number all the candidates on the ballot paper in order of their preference. If one candidate receives more than 50% of the first-preference votes then they are declared elected. If not, the candidate with the least votes is eliminated and their votes are redistributed according to the second preferences of each person who voted for that candidate. This process continues until one candidate passes the 50% benchmark. Continue reading

Global Warming Contrarians Part 7: State of the Climate

Claim: There’s no evidence that the global climate is warming. Why worry about a problem that’s invisible?

Fact: Just about any aspect of climate you care to look at does show signs of global warming.

The US National Oceanic and Atmospheric Administration have recently released their 20th annual State of the Climate report. The report is ostensibly about the climate in 2009, but because 2009 was the end of a decade the authors decided to take a longer-term view.

According to the press release, the report

draws on data for 10 key climate indicators that all point to the same finding: the scientific evidence that our world is warming is unmistakable. More than 300 scientists from 160 research groups in 48 countries contributed to the report, which confirms that the past decade was the warmest on record and that the Earth has been growing warmer over the last 50 years. Continue reading

Scientific Opinion versus Media Balance

Renegade Conservatory Guy has created an infographic showing the discrepancy between scientific opinion on global warming and public opinion. I think this speaks for itself.

Mid-Year Update on Global Temperatures

NOAA’s National Climatic Data Center (NCDC) have announced that the Earth has just experienced its warmest June on record, 0.68°C warmer than the 20th-century June average of 15.5°C. Most of the globe was warmer than usual, with the highest temperature anomalies seen in eastern and western Asia, eastern North America, western South America, and most of the Atlantic Ocean. The only surface temperatures much cooler than average were in the eastern Pacific and Southern Oceans. The warmest June is particularly notable in that it follows the warmest March, April, and May.

(Global temperatures are usually given as anomalies relative to a 20th century average because they are easier and more useful to compare than absolute temperatures. The last month with a temperature below average was February 1985.)

Let’s quickly recap the year so far. It began with an unusually cold winter in northern land areas, related to the Arctic Oscillation (AO), which in February 2010 was at its most negative value on record, moving heat to Arctic regions. Despite the unfortunate and disproportionate impact this had on public opinion, January was a relatively warm month globally, and the Southern Hemisphere had its warmest February on record. Continue reading

Global Warming Contrarians Part 1.1: Amateur Temperature Records

After a two-month hiatus, I’ve finally completed the next installment in my increasingly non-linear series of posts examining the (mostly bad) arguments against the reality of global warming. Originally I had planned out a sort of arc of subjects to cover, but as I learn more about climate science, I find I want to go back to what I’ve written previously and add new information, or explain things in a different way — that’s why I’m calling this post Part 1.1. So here’s a continued version of my argument in favor of the surface temperature record. I discuss one of the latest trends in the climate blogosphere: amateur temperature records.

Claim: The surface temperature record cannot be trusted.

Fact: Recent developments should make us even more confident that the record can indeed be trusted.

As I’ve mentioned before, there are three main surface temperature records, compiled by NOAA’s National Climatic Data Center (NCDC), NASA’s Goddard Institute for Space Studies (GISS), and the University of East Anglia’s Climatic Research Unit (CRU), respectively. There is also at least one other that is lesser known: that of the Japan Meteorological Agency (JMA). All of these analyses have been compiled by professional research organizations and published in peer-reviewed scientific journals. All of them converge on a common result: the Earth’s surface has warmed about 0.7°C in the last 100 years, and about 0.18°C/decade in the last 25 years. So all the records taken together can be seen as a sort of “consensus temperature record”, in which the observed warming is well outside the error bars.

Unfortunately, some members of the public are inclined to believe that this convergence is all part of a huge conspiracy, that scientists are not allowed to get results that contradict the pre-determined conclusions of the so-called “establishment”. This view is entirely at odds with my understanding of how science works, but it’s a depressingly common one. It’s also a difficult view to argue with, because the more positive results you cite, the bigger the conspiracy must be in the eyes of the conspiracy theorists. But what if there was a global temperature analysis entirely independent of the scientific establishment? Continue reading

2010 Shaping Up To Be Warmest Year

The Earth has just experienced its warmest March, April, and May on record, according to the US National Climatic Data Center (NCDC), and 2010 is well on track to becoming the warmest year on record.

March 2010 was not only the warmest March globally, but also the third warmest month of all time. I don’t mean it was the third warmest month in terms of absolute temperature — Julys are always several degrees warmer than Januarys — but after the seasonal cycle is filtered out. To be precise, the global temperature was 0.77°C above the 20th century average of 12.7°C for March, the third highest monthly temperature anomaly after February 1998 and January 2007. (In climatology, anomalies are generally more useful than absolute temperatures.)

The global temperature for this April was not far behind, at 0.73°C above the April average of 13.7°C. Similarly, it’s both the warmest April on record and the sixth warmest month of all time. In Australia, May 2009 – April 2010 was the warmest 12-month period on record in the states of Victoria and Tasmania, and the third warmest for the continent overall.

Although this year’s El Niño has now come to an end, May 2010 was still the warmest May (and 13th warmest month), at 0.69°C above the average 14.8°C. Unusually warm temperatures were seen in eastern Europe, Siberia, eastern North America, and large parts of Africa; meanwhile, the Southern Ocean cooled. Continue reading

CO2 hits 390 ppm

The level of carbon dioxide (CO2) in the atmosphere, as measured at Mauna Loa, has just ticked over to 390 ppm.

Actually, that’s not quite true — the level is 392.39 ppm as of April. But CO2 levels are slightly higher during the northern spring than the southern spring, because the Northern Hemisphere has more land and hence more vegetation breathing out CO2. Once you adjust for this seasonal cycle, then the current CO2 level is 389.64 ppm — which rounds to 390.

I first got interested in global warming about four years ago when I read TIME magazine’s special issue on global warming. At that time, the CO2 level (again, seasonally adjusted) was around 382 ppm. It reached 383 ppm by December 2006, 384 ppm by April 2007, 385 ppm by November 2007, 386 ppm by June 2008, 387 ppm by January 2009, 388 ppm by August, 389 ppm this February, and now 390 ppm. All these numbers come from measurements made at Mauna Loa observatory, but wherever you look you’ll get similar results.

CO2 at Mauna Loa since 2006. (Source: Earth System Research Laboratory)

Continue reading

Global Warming Contrarians Part 2.1: Cooling Trend or Noise?

In Part 2 of this series of posts examining the (mostly bad) arguments against the reality of global warming, I debunked the oft-heard claim that global warming stopped in 1998. Basically, the people who make that claim are just joining endpoints, rather than looking at the trend from 1998 to now. But there is a slightly more sophisticated version of that argument, which does actually look at the trend. It goes something like:

Claim: There’s been global cooling since 2001 (or 2002), and no significant warming since 1995.

Fact: Firstly, the exact trend varies from one record to another. The NCDC record shows a slight negative trend for 2001-2009, and a more negative trend for 2002-2009. GISTEMP shows a very slight positive trend for 2001-2009, and a negative trend for 2002-2009. Both trends are decidedly negative in the HadCRUT3 record. But all three records show a positive trend for 2000-2009.

In earlier posts I’ve mainly cited the NCDC record when talking about surface temperatures; for the sake of consistency, I’ll continue to do so here. According to NCDC, the trends are +0.07°C/decade for 2000-2009, -0.03°C/decade for 2001-2009, and –0.08°C/decade for 2002-2009. So technically, we have seen about nine years of “cooling”. But is that enough to indicate a change in the long-term trend? Continue reading

Global Warming Contrarians Part 6: Global Cooling in the Mid-20th Century

Here, at last, is the much-delayed sixth instalment in my ongoing series of posts on the (mostly bad) arguments that contrarians make against global warming. (A list of earlier parts in the series can be found here.)

In this post, I want to clear out of the way one more factoid that contrarians hold up as evidence against greenhouse warming:

Claim: In the mid-20th century, CO2 levels rose but temperatures dropped.

Fact: Obviously, there are other influences on global climate as well as CO2. Since the 1970s, CO2 has clearly emerged as the dominant influence, and temperatures have risen by 0.17°C/decade. However, earlier in the 20th century when CO2 was rising more slowly, there were large variations in the temperature trend, most notably an accelerated warming up to the 1940s and a slight cooling from the 1940s to the 1960s.

Radiative forcing is a measurement of how much energy the planet is gaining or losing due to a particular influence on climate. To fully explain the observed temperature changes, we have to take into account all forcings, not just CO2. Other important forcings include solar activity (natural), other greenhouse gases (in this case anthropogenic), and aerosols (a mixture of natural and anthropogenic). The latter was probably the most important factor in mid-20th century climate change. Continue reading

Introducing “2010 Global Temperature Watch”

There’s a good chance that 2010 will be the warmest year in the global surface temperature record. So I figured it’s worth keeping an eye on global temperatures this year. I’ll be posting regular updates on a new page called “2010 Global Temperature Watch”.

Here’s a sample:

16 April 2010

According to NCDC, the global temperature for March 2010 was 0.77°C above the 20th century average — not only the warmest March, but also the third highest anomaly on record for any month.

17 April 2010

The recent volcanic eruption in Iceland is not expected to affect global temperature as the ash did not rise high enough to get into the stratosphere.