Record highs of atmospheric carbon dioxide measured in Hawaii.

The measured levels of carbon dioxide which are present in the Earth’s atmosphere were recorded at over 400 parts per million (ppm) for the first time in human history at the Earth System research observatory on Mauna Loa, Hawaii. The American observatory has made daily recordings of the carbon dioxide levels in the atmosphere since 1958 and so gives a clear record of the oscillations and temporal variations in carbon dioxide levels in our atmosphere.

To investigate the carbon dioxide levels in the atmosphere before stations like this started recording, scientists look at trapped bubbles within old ice, as well as the chemical composition of carbon-bearing species to estimate the amount of carbon dioxide in older atmospheres. Over the past 200 years the amount of carbon dioxide in our atmosphere has increased from 280 ppm to 400 ppm, due to the burning of fossil fuels since the industrial revolution, and this value is higher than any recorded over the past 800 thousand years. The last time that carbon dioxide levels were this high, was 3-5 million years ago in the Pliocene period, when the climate was much warmer than today and was before modern humans had evolved. Carbon dioxide is a greenhouse gas which helps to trap energy from the sun’s rays and so as the levels in the atmosphere increase, the temperature across the planet will increase, ice sheets will melt and sea levels will rise, among other phenomena, in turn affecting the global population.

The value of 400 ppm is not so unusual in itself; however, scientists are concerned at the rate at which this value is rising, and the human forcing of the natural climate system. There is uncertainty with exactly how this increase in carbon dioxide will affect the climate in the future, however, surpassing this level should encourage people to take action to reduce the amount of carbon dioxide emissions and consider the potential damage being caused.