Researchers at Northern Arizona University have identified major measurement errors in Climate TRACE, a global emissions database co-founded by former Vice President Al Gore. The study reveals that the database systematically undercounts carbon dioxide emissions from vehicles in American cities.
The research, conducted across 260 U.S. cities, found an average undercount of 70% for transportation emissions. Some urban areas show discrepancies exceeding 90%, meaning actual vehicle emissions from those cities are far higher than the database reports. These gaps have serious implications for climate policy and urban planning decisions that rely on accurate emissions data.
Climate TRACE aggregates emissions information from satellites, sensors, and other sources to track greenhouse gas output globally. The organization positions itself as a transparent tool for climate accountability. However, the Northern Arizona University team's analysis suggests the methodology misses substantial portions of real-world transportation pollution.
The severity of the undercount varies by city. Larger metropolitan areas with complex traffic patterns appear particularly vulnerable to measurement errors. The researchers did not specify which cities showed the largest gaps, but the 90% threshold indicates some databases are capturing only a fraction of actual vehicle emissions.
This finding raises questions about how emissions inventories inform climate targets and investments. Cities and countries rely on such data to set reduction goals, allocate climate funding, and track progress toward net-zero commitments. If baseline measurements are off by 70% or more, the entire foundation for emissions reduction planning becomes unreliable.
Climate TRACE has not yet publicly responded to the Northern Arizona University study. The research underscores a broader challenge in climate science: obtaining accurate, comprehensive emissions data across diverse geographies and sources. Satellite imagery and remote sensing tools have limitations in urban environments where buildings, trees, and infrastructure create measurement blind spots.
The implications extend beyond vehicle emissions. If transportation data in Climate TRACE is significantly undercounted, other sectors tracked by the database may face