Experts attending a climate conference in Milan this week have raised concerns over the slow pace of progress in carbon dioxide removal (CDR) technologies, which are considered vital for mitigating global warming. Despite increased awareness of climate risks, research and investment in CDR remain limited, and the sector is still in its infancy.

Massimo Tavoni, a professor of climate change economics at the Polytechnic University of Milan, noted a decline in interest compared to just a few years ago. He attributed this shift partially to geopolitical factors, citing changes in U.S. leadership and the impact of ongoing conflicts. The Polytechnic University of Milan jointly hosted the conference with the Euro-Mediterranean Centre on Climate Change (CMCC), an Italian research foundation focused on climate science.

According to the latest report titled “The State of Carbon Dioxide Removal,” currently, CDR efforts account for only about 5 percent of global annual CO2 emissions. Nearly all of this, approximately 99.9 percent, relies on natural processes mainly through reforestation. Trees absorb CO2 through photosynthesis, storing the carbon in their trunks, branches, and roots. Large-scale reforestation efforts across continents—including China, the United States, Europe, and Brazil—are helping to sequester emissions largely produced by fossil fuel combustion. However, the report highlights stagnation in the expansion of tree plantations, which face competition from agricultural land uses.

The Milan event drew scientists from several countries, including the United States, Germany, China, and Australia, who presented recent research on air-based CDR methods. Unlike carbon capture and storage technologies, which filter CO2 emissions directly from industrial sources such as power plants, carbon removal focuses on extracting CO2 already dispersed in the atmosphere at low concentrations. Researchers emphasized that while CDR is essential, it cannot replace urgent action to reduce current emissions. Preventing further atmospheric CO2 accumulation remains the primary objective, with removal methods aimed at addressing residual emissions.

Among the strategies discussed were processes such as pyrolysis, which involves heating plant residues without oxygen to create biochar—a porous material beneficial for soil health and nutrient retention. Other approaches include capturing CO2 following the combustion of biomass and agricultural residues. These methods not only sequester carbon but may also provide agricultural benefits.

Overall, the conference underscored the need for accelerated development and scaling of carbon removal technologies alongside aggressive emissions cuts to meet global climate goals.