Oil discovery often increases military spending, Mr. Perlo-Freeman says, because – unlike taxes – the revenues carry little political cost, the oil and gas infrastructure justifies increased protection, and the development of natural resources tends to exacerbate tension and conflict.
In Nigeria, for example, SIPRI found that “the massive environmental damage caused by oil extraction and the lack of benefit to oil-producing regions has generated grievances.” Chad, as well, has increased military spending in an attempt to quell domestic conflict. Chad’s oil infrastructure was built up with cheap loans from the World Bank. The global lending agency pulled out of the project when it became clear that the government was spending oil revenues on defense instead of development, says Perlo-Freeman.
In Central Asia, Azerbaijan has used oil revenues to beef up forces along its border with Armenia, which has traditionally had a stronger army and enjoys strategic terrain advantages. The International Crisis Group said in a report last year that Azerbaijan's stronger military could put the fragile truce with Armenia under threat.
“Azerbaijan has been playing catch-up with Armenia,” says Perlo-Freeman, noting their conflict over the disputed Karabakh region.
In absolute terms, the US and China increased military spending the most over the past decade.
China, which regards its military budget as a state secret, spent an estimated $100 billion on it in 2009, a 217 percent increase from 2000, according to SIPRI. The only other Asian country in the top 15 was India, which spent $36.3 billion on its military in 2009.