We all know that the currents atmospheric carbon dioxide levels are not, shall we say, ideal. But according to recent measurements from NOAA’s Mauna Loa Atmospheric Baseline Observatory, published by NOAA and Scripps Institution of Oceanography, observations from May 2019 showed the highest seasonal peak recorded in 61 years, reaching a whopping 414.7 ppm.
Scientists use the month of May as a special marker to evaluate atmospheric carbon dioxide levels because it is when these levels are the highest, as plants have just begun blooming in the northern hemisphere and have yet to consume (and remove) huge quantities of CO2 from the atmosphere. This seasonal cycle of CO2 levels is known as the Keeling Curve, after Charles Keeling, who was the first person to notice it.
Compared to measurements from last May, this May was 3.5 ppm higher and records the second-highest annual jump yet. It’s been five years since observations on atmospheric carbon dioxide first reached over 400 ppm in 2014 and they have continued to rise since then. According to NOAA, “The early years at Mauna Loa saw annual increases averaging about 0.7 ppm per year, increasing to about 1.6 ppm per year in the 1980s and 1.5 ppm per year in the 1990s. The growth rate rose to 2.2 ppm per year during the last decade.” There is no doubt that anthropogenic emissions are behind this steep rise.
Pieter Tans, a senior scientist with NOAA's Global Monitoring Division, commented, “It's critically important to have these accurate, long-term measurements of CO2 in order to understand how quickly fossil fuel pollution is changing our climate. These are measurements of the real atmosphere. They do not depend on any models, but they help us verify climate model projections, which if anything, have underestimated the rapid pace of climate change being observed."
Data from Mauna Loa provides important information for NOAA's Global Greenhouse Gas Reference Network, a database that collaborates on climate science projects around the world.