There's a lot more to it than climate change
If this were true, you would expect to a delay by a couple of years from the onset of El Nino. It takes a year for crops to fail, and more time for a country to go through its food stores. For example, the current crisis in Somalia didn't just happen this year, famine (again) has been building there for years. So rather than occurring the same year as El Nino, you might have conflicts start even as La Nina is beginning. The degree of conflicts is also influenced by the weather. During wet, rainy years it's difficult to mount a major campaign, especially with the poor infrastructure of many of these countries. There's a reason why the war in Afghanistan shuts down every winter. The same happened with the Civil and Revolutionary Wars in America.
Most of the major conflicts of this period (Korea, Vietnam, the two Iraqi wars, the two wars in Afghanistan, the former Yugoslavia, etc.) were not motivated by food shortages. They were either proxy wars between the US and the Soviet Union, or wars over terrorist acts. Hence most of the wars in this article have to be the small regional wars that erupted in Africa and elsewhere. Many of these were former British Commonwealth or French controlled countries in Africa and Asia. While these countries deserved their independence, most of them were left with very weak governments that fell apart under regional and tribal pressures. They were powder kegs just waiting for a spark.
Developed areas such as the US and Europe have lots of ways to deal with the stresses of crop failures. While the situation there could break down to the point you have active civil unrest, it won't happen for a long time. There's no evidence El Nino caused any conflicts there because there have been no conflicts (the article conveniently left out that agricultural production in the US at least is very much affected by El Nino).
Rather than climate change, the biggest factor by far in causing future conflicts will be global population growth. The global population by 2050 will grow to about 9 billion, which is beyond the current means of the planet to feed itself even without global warming.
