Is global warming really caused by humans?

Global warming caused by humans?

Since 1958 scientists observing in Hawaii have taken continuous measurements of atmospheric carbon dioxide. The levels go up and down  by changing the seasons, but overall they show a relentless rise. Bubbles of gas from ice cores and the chemical composition of fossil shells provide us with a record of atmospheric carbon dioxide going back millions of years. There have been warm periods in the past where carbon dioxide was at levels similar to those seen today. However, the rate of change that we see today is exceptional: carbon dioxide levels have never risen so fast. By 2000 they were 17% higher than in 1959. Accompanying this rapid increase in carbon dioxide we see a rise in average global temperatures. Warming in the past 100 years has caused about a 0.8 C increase in global average temperature. Eleven of the 12 years in the period 1995 - 2006 rank among the top 12 warmest years since 1850. There is little doubt that humanity is responsible for the rapid rise in carbon dioxide levels. The rise in temperature that has accompanied our fossil fuel addiction seems too much of a coincidence to just chance. Most people now agree that our actions are having an effect on Earth's climate.