China’s poorest counties are transitioning towards low-carbon poverty alleviation

• The poorest counties have been shifting to a “high development-low carbon” state. • Improved model enables more accurate assessments of the coupling coordination state. • Carbon emission intensity declined in most counties between 2010 and 2020. • Multidimensional poverty has significantly improved over the past two decades. Low-carbon development in poverty-stricken areas is crucial for the Sustainable Development Goals. However, the relationship between poverty alleviation and carbon emissions in impoverished regions remains unclear. This study calculated land-use carbon emissions of 505 counties in China’s contiguous poor areas, which suffer from extreme poverty and are the most difficult to lift out of poverty, established evaluation frameworks for carbon emissions efficiency and multidimensional poverty alleviation, and employed an improved coupling coordination model to assess the relationship. Results showed that all counties achieved remarkable multidimensional poverty alleviation from 2000 to 2020 while the speed varied among regions. After initial deterioration, emission efficiency exhibited significant improvements during 2010–2020. This reversal was mainly driven by reduced carbon intensity and carbon emissions per unit of construction land. Analysis revealed 505 counties’ transformation from an uncoordinated “low development-low carbon” state toward a sustainable “high development-low carbon” state. These findings evidence that poverty alleviation development and low-carbon target can be compatible, offering valuable insights for sustainable development in global underdeveloped regions.