Carbon in the Air: Why Greenhouse Gases Kept Rising Despite the Pandemic

Redacción HC
18/08/2023

In 2020, as cities fell silent and global emissions dipped due to COVID-19 lockdowns, one might have expected Earth’s atmosphere to catch a break. Yet, the air told a different story. Greenhouse gas concentrations—particularly carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O)—continued to climb, reaching new record levels. This unsettling revelation comes from the World Meteorological Organization’s (WMO) Greenhouse Gas Bulletin No. 17, which offers a comprehensive overview of atmospheric data through the end of 2020.

Based on global in situ measurements, the report paints a picture of persistent climate pressure, even in the face of temporary emission reductions. But why didn’t the slowdown in human activity make a dent? And what does this say about the future of climate policy?

The Climate Question: Tracking Invisible Drivers of Warming

Greenhouse gases are the invisible forces driving climate change. CO₂, CH₄, and N₂O differ in their chemical lifetimes and radiative properties but share one common feature: once released, they stick around. This report focused on how these gases evolved during a year of global disruption and whether the Earth's natural systems—like forests and oceans—are still absorbing enough to help stabilize the atmosphere.

The central question posed by the WMO was clear: How did greenhouse gas levels evolve in 2020, and what are the implications for climate trends and policy effectiveness?

A Global Network of Eyes on the Atmosphere

To answer that, the report relied on data from the WMO’s Global Atmosphere Watch (GAW) program, which maintains a robust monitoring network. In 2020, CO₂ was tracked at 139 stations, CH₄ at 138, and N₂O at 105, providing a dense dataset of surface-level mole fractions (in ppm or ppb). These were reported with a statistical confidence interval of 68%.

For CO₂, scientists also analyzed O₂/N₂ ratios—especially from observatories like Jungfraujoch—to infer how much carbon was absorbed by land-based vegetation and oceans. They compared current measurements to pre-industrial levels and calculated radiative forcing using NOAA’s AGGI (Annual Greenhouse Gas Index).

While the network is comprehensive, the report acknowledged gaps in tropical coverage, including under-monitored regions like the Amazon Basin and sub-Saharan Africa—areas critical to understanding global carbon dynamics.

Record Highs: What the Data Reveals

Despite the global pause in human activity, the numbers rose:

• CO₂ reached 413.2 ppm, 149% above pre-industrial levels.
• CH₄ hit 1889 ppb, or 262% of pre-industrial concentration.
• N₂O climbed to 333.2 ppb, marking a 123% increase since pre-industrial times.

All three surpassed previous records.

Year-on-year increases remained high:

• CO₂ rose by 2.5 ppm, slightly below 2019 but above the decade average (2.4 ppm).
• CH₄ rose by 11 ppb, exceeding its 10 ppb/year average.
• N₂O increased by 1.2 ppb, also above its long-term average of 0.99 ppb/year.

According to the AGGI, the total radiative forcing from long-lived greenhouse gases increased 47% since 1990, with CO₂ accounting for roughly 80% of this growth. In 2020, the combined effect of all greenhouse gases amounted to an atmospheric warming potential equivalent to 504 ppm of CO₂ alone.

These figures are alarming. As the report notes, “the accumulation of greenhouse gases is consistent with pathways that lead to a global warming of 1.5 to 2°C or more.”

Earth’s Natural Absorbers Are Still Working—But for How Long?

One striking finding concerns the "airborne fraction" of CO₂—the percentage of emissions that remain in the atmosphere after natural absorption. In 2020, about 44% of CO₂ stayed aloft, while terrestrial ecosystems absorbed 27% and oceans took up 29%. While these ratios remained roughly stable, scientists worry that warming temperatures, shifting precipitation, and ocean acidification could weaken these natural sinks.

Indeed, the report warns that “carbon sinks may deteriorate under climate stress,” making mitigation harder in the future.

Beyond the Pandemic: Policy Lessons and Societal Urgency

The persistence of greenhouse gas growth during a year of global lockdowns underscores one key reality: temporary reductions aren’t enough. To meet the Paris Agreement targets, structural and sustained emission cuts are needed.

The AGGI index is highlighted as a crucial policy tool, offering a straightforward measure of climate progress that can inform national reviews and international negotiations. The WMO recommends its widespread use in forums like COP conferences.

There’s also a social dimension. “Even drastic short-term emission drops don’t immediately affect atmospheric concentrations,” the report explains—meaning public communication must focus on long-term commitments rather than quick wins.

Recommendations from the Report

• Expand GAW monitoring, particularly in data-poor tropical zones.
• Integrate satellite and isotopic data to better track emissions sources and sinks.
• Leverage AGGI as a transparent, science-based metric in climate policymaking.

Conclusion: The Air Keeps the Score

This bulletin is a sobering reminder that the atmosphere records every molecule we emit. It tells us whether we're on track or falling short. Even a global pandemic couldn’t meaningfully disrupt greenhouse gas accumulation.

The WMO’s findings challenge us to move beyond symbolic climate actions. We need scalable, verifiable, and global changes in how we produce energy, grow food, and manage ecosystems.

The numbers won’t lie.

Topics of interest

Climate Pollution