Yogi Berra, the famously philosophical former American baseball player, once noted that: “The future ain’t what it used to be.”

And he was right. Our present is the future Berra was talking about, and in terms of the climate, it “ain’t what it used to be” for at least one million years. NASA scientist Dr. Charles Miller highlighted the unprecedented levels of CO2 emissions now in the atmosphere, which have been at and above 400ppm for the last several months – levels that humanity has never experienced before.

Current [atmospheric] CO2 values are more than 100 ppm higher than at any time in the last one million years (and maybe higher than any time in the last 25 million years). This new record represents an increase of 85 ppm in the 55 years since David Keeling began making measurements at Mauna Loa. Even more disturbing than the magnitude of this change is the fact that the rate of CO2 accumulation in the atmosphere has been steadily increasing over the last few decades, meaning that future increases will happen faster. When averaged over 55 years, the increase has been about 1.55 ppm CO2 per year. However, the most recent data suggest that the annual increase is more than 2.75 ppm CO2 per year.

These increases in atmospheric CO2 are causing real, significant changes in the Earth system now, not in some distant future climate, and will continue to be felt for centuries to come. We can study these impacts to better understand the way the Earth will respond to future changes, but unless serious actions are taken immediately, we risk the next threshold being a point of no return in mankind’s unintended global-scale geoengineering experiment.

And what about our future? Based on projections, it ain’t what is used to be either.