Findings: Climate key to wealthy states

A good frost may have made all the difference when it came to determining the wealth of nations.

United States economists William Masters, at Purdue University, and Margaret McMillan, at Tufts University, draw the conclusion by linking economic and new global climate data.

Their research, published in the Journal of Economic Growth , suggests that annual hard frosts play two critical roles that influence which parts of the world are rich and which are poor.

First, frost helps farmers increase agricultural productivity. It allows a build-up of organic matter that leads to fertile topsoil. In the tropics, insects and microbes break down topsoil rapidly.

It also ensures the soil is moist for spring planting.

Second, frost helps people control disease, particularly malaria, by making insects dormant.

Masters said: "The broad puzzle is why are poor countries in geographic tropics, and most of the wealthy countries are not in the tropics. For the first time, we can put detailed biophysical data into economic models to try to understand how climate and geography have influenced economic performance."

There are exceptions to the rule. North Korea and Mongolia are temperate and poor, while the city states Hong Kong and Singapore are tropical and rich.

However, the economists point out that the former are both isolated and have been subjected to totalitarian regimes, while the latter are trade centres that do not depend on local resources to accumulate their wealth.

The economies of the wealthiest nations no longer rely on agriculture but they were able to build capital in the times when they did.

Tropical nations could now catch up through investment in public health and agricultural research.