But over the last hundred years, since good record-keeping began, temperatures have risen only about half a degree Celsius. That increase occurred during the 1930s, and temperatures have decreased slightly since then. A team of NASA scientists who monitor orbiting satellites has noted a statistically significant cooling trend, minus 0.048 degrees Celsius per decade in recent years. Indeed, this spring's flood and our ongoing lousy weather would support the cooling theory. They were caused by huge snowfalls and an unusually long freeze in the Lake Winnipeg drainage basin.
Carbon dioxide is released when fossil fuels like coal and oil are burned.
Levels today are 27 percent higher than at the start of the industrial revolution. But carbon dioxide makes up only 0.035 percent of the atmosphere. Some scientists point out that a warmer world would also have an upside. It is not unreasonable to view our history as one long struggle to keep warm. More carbon dioxide in the air would lead to more luxuriant plant growth and greater crop yields.