Atmospheric carbon dioxide has risen again, for the seventh consecutive May.

Last month, average levels peaked at 414.7 parts per million (ppm). That is a 3.5 ppm increase on last year (411.2 ppm) and the highest seasonal peak on record since 1958, with levels topping 415 ppm on May 11, 2019.

The data was collected at NOAA's Mauna Loa Atmospheric Baseline Observatory on the Big Island of Hawaii, where scientists have been monitoring air quality since the 1950s. 

Annual levels of atmospheric carbon dioxide tend to peak in May – following months of plant and soil generated CO₂ emissions in the fall, winter, and early spring and before plants really start to remove that buildup in late spring and summer. According to NOAA, May 2019 saw the second highest annual jump recorded.

"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," Pieter Tans, a senior scientist with NOAA's Global Monitoring Division, said in a statement.

"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."

Indeed, while predicting future climate change is a tricky business due to the various variables and feedback loops, recent research would indicate past estimates have erred on the conservative.

Last year, the  Intergovernmental Panel on Climate Change (IPCC) published a landmark report warning against the catastrophic consequences of exceeding 1.5°C warming above pre-industrial levels before 2100, while emphasizing the dangers of reaching 2°C warming.

Meanwhile, some of the most recent climate models predict we're on track to see a 3 to 5°C rise by the end of the century, a situation that would cost the US a jaw-dropping $23 trillion a year. (That is equivalent to a third of the current global GDP and 7+ percent of projected GDP in 2100).

And if all that isn't enough to have you quaking in your boots, a thinktank published a report this week suggesting humanity's survival could be on the line. The authors' hypothetical scenario concludes there is a "high likelihood of human civilization coming to an end" by 2050 if we don't take urgent action and soon.

Years of data collected at Mauna Loa reveals a steady increase in atmospheric carbon dioxide, with annual increases averaging at 0.7 ppm per year to begin with and rising to increases averaging 1.6 ppm per year in the 1980s. This declined somewhat in the 1990s (1.5 ppm per year), only to increase again in the 21st century. Over the last decade, the growth rate has risen again to 2.2 ppm per year, breaching 400 ppm for the first time ever in May 2014.

There is abundant and conclusive evidence that the acceleration is caused by increased emissions, Tans added.  

While this all sounds a bit doom and gloom, scientists do believe there is still time to act.

"The science is clear; for all the ambitious climate action we’ve seen, governments need to move faster and with greater urgency," UN Environment Deputy Executive Director Joyce Msuya said in a statement.

"We’re feeding this fire while the means to extinguish it are within reach."