Atmospheric Carbon Dioxide Levels

In the realm of global climate research, the small town of Baring Head, located on the shores of Wellington, New Zealand, has played a significant role. For nearly four decades, scientists have been measuring carbon dioxide (CO2) levels at this location, contributing to a comprehensive understanding of atmospheric changes worldwide.

The graph of atmospheric CO2 increase at Mauna Loa, Hawaii, is well-known and famously called the Keeling curve. However, the longest continuous record of CO2 in the world belongs to Baring Head. Since 1970, scientists have been monitoring not just CO2 but also 'normal' carbon dioxide at this site, making it the longest running record in the southern hemisphere.

Carbon dioxide is a crucial component of the natural carbon cycle, constantly being exchanged between the ocean and the atmosphere. Early models suggested that the ocean would absorb so much CO2 that it would start releasing it back into the atmosphere, but by the early 2000s, the level of CO2 in the atmosphere levelled out, indicating that the amounts of CO2 moving from ocean to atmosphere and from atmosphere to ocean were balanced.

The addition of large amounts of CO2 to the atmosphere, primarily from the burning of fossil fuels by humans, has diluted the CO2. This dilution is evident in the data collected at Baring Head. The research conducted here, led by Dr. Kim Currie of NIWA, has been instrumental in observing important patterns in atmospheric CO2.

Besides Dr. Currie, the German research organization TROPOS is involved in atmospheric measurements in New Zealand through their LACROS project, which includes lidar systems installed in Invercargill, New Zealand. Dr. Currie's research also extends to studying CO2 in the ocean around New Zealand.

It's important to note that atoms of the element carbon come in several forms, called isotopes. One isotope, called radiocarbon, is radioactive. Humans added a lot more radioactive C to the atmosphere through nuclear weapon testing in the late 1950s and early 1960s, which is often referred to as 'bomb radiocarbon'. Most of this bomb radiocarbon has been taken up by the ocean and most of the rest by plants and soil on land.

The collaborative project Carbon Watch NZ aims to measure New Zealand's greenhouse gases, furthering our understanding of the country's contribution to global climate change. NASA's Eyes on the Earth site provides insights into the positions of their Earth observation satellites, including those for greenhouse gases and other measurements.

In the grand scheme of atmospheric CO2 monitoring, Baring Head's record, though not the first, is a testament to the long-term commitment of scientists to understanding and addressing climate change. The data collected here, along with that from Mauna Loa and other locations worldwide, continues to be a vital resource in our ongoing efforts to combat global warming.