Why the likelihood of war has increased since the end of the cold war?

Answer 1

There was a balance between superpowers during the Cold War, and neither side was suicidal.
Now, we have more scattered power, and non-government actors have entered the combat role too. And a number of them are suicidal.
Also, the USSR suppressed some conflicts within their borders. Now these are no longer under control.
So now, the next major conflict is brewing. The conflict between Capitalism and Socialism has calmed down, with most Western countries having some combination of the two. Now a religious conflict is arising, with aggressive Islam.

Answer 2

During the Cold War, the nuclear standoff between the USA and the USSR was reason enough to funnel vast amounts of money into defense. Now that it's over, the military/industrial complex needs some other excuse to continue to receive hundreds of billions of dollars. A war is the ideal excuse.

Answer 3

Iran: Why does Bush invoke the threat of World War III?
Part 1: Iran’s strategic position
By Alex Lantier
30 November 2007
http://www.wsws.org/articles/2007/nov2007/iran-n30.shtml

excerpt:

In remarking that current tensions over Iran threatened to provoke World War III, President Bush inadvertently acknowledged the profound tensions tearing at the political and economic foundations of world capitalism. Plans for a US war against Iran are baring the rivalries between the different cliques of the world bourgeoisie—American, European, Russian, Chinese, etc.—and their preparation for war against each other.

They are again affirming the basic contradiction identified by the great Marxists of the early twentieth century: the clash between the global character of mankind’s productive forces and the fetters imposed upon them by the capitalist nation-state system.

The idea that the current Middle East conflicts would remain localized in the case of US aggression against Iran is historical and political blindness. Globalization on a capitalist basis—with a ferocious competition inside the world bourgeoisie for the global division of profits, and where the living standards of the working classes of each region are pitted against each other in a race to the bottom—has dangerously outlived itself. It threatens not only a further eruption of US militarism in the Middle East and the destabilization of world finance, but a horrific global military conflagration.

Answer 4

I don't think the likelihood of war has changed since the dawn of civilization.