The relentless rise of atmospheric CO2 since 1950

The Keeling Curve shows atmospheric CO2's relentless rise (click for full size)

In 1958, Charles David Keeling began measuring atmospheric carbon dioxide at the Mauna Loa Observatory in Hawaii. What he discovered would become one of the most important datasets in climate science—a relentless, accelerating rise in CO2 concentrations that shows no signs of stopping.

CO2 concentrations have risen from ~315 ppm in 1958 to over 420 ppm today

The numbers tell a stark story ​

When measurements began in the late 1950s, atmospheric CO2 stood at approximately 315 parts per million (ppm). Today, we've crossed 420 ppm—a level not seen in over 3 million years. But it's not just the increase that's alarming; it's the acceleration.

Consider the pace of change:

• 1958-1988: CO2 rose from 315 to 350 ppm (35 ppm in 30 years)
• 1988-2018: CO2 rose from 350 to 410 ppm (60 ppm in 30 years)
• Current rate: Increasing by ~2.5 ppm per year

Why Mauna Loa matters ​

The Mauna Loa Observatory sits at 11,135 feet elevation on the Big Island of Hawaii, far from major pollution sources. This isolation makes it ideal for measuring Earth's "background" CO2 levels—what's actually in our global atmosphere, not just local pollution.

The pre-industrial baseline ​

To understand the full scope of change, we need to look beyond 1950. Ice core data reveals that for the 10,000 years before the Industrial Revolution, atmospheric CO2 remained remarkably stable around 280 ppm.

Period	CO2 Level	Context
Pre-1750	~280 ppm	10,000 years of stability
1950	~310 ppm	Early industrial impact
1990	~355 ppm	Acceleration begins
2024	~422 ppm	Highest in 3+ million years

The industrial era has fundamentally altered Earth's atmosphere

What drives the acceleration? ​

The accelerating rise reflects our expanding global economy and energy use:

• Fossil fuel combustion: Coal, oil, and natural gas burning releases ~36 billion tons of CO2 annually
• Deforestation: Reduces Earth's capacity to absorb CO2
• Industrial processes: Cement production alone accounts for ~8% of global emissions

The atmosphere doesn't care about our politics or economics. It just responds to physics. Dr. Ralph Keeling, current director of the CO2 program

The path forward ​

Understanding this trend is crucial because CO2 is a primary driver of global warming. Each ppm increase traps more heat in Earth's atmosphere. The Paris Agreement aims to limit warming to 1.5°C, but at current rates, we'll likely exceed the CO2 levels compatible with that goal within a decade.

The Keeling Curve stands as both a scientific achievement and a stark warning. It's the most direct evidence we have of humanity's impact on Earth's atmosphere, measured breath by breath, year after year, with no ambiguity in its message: we are fundamentally altering our planet's climate system at an unprecedented rate.