School Notes: School of the Environment
September/October 2024

Surprising findings from 2024 EPI

The tiny Baltic nation of Estonia has surged to the top of the Environmental Performance Index. The 2024 EPI, published by the Yale Center for Environmental Law and Policy and Columbia University’s Center for International Earth Science Information Network, ranks 180 countries based on 58 performance indicators to track progress on mitigating climate change, promoting environmental health, and safeguarding ecosystem vitality. The data evaluates efforts by the nations to reach UN sustainability goals, the 2015 Paris Climate Change Agreement, as well as the Kunming-Montreal Global Biodiversity Framework. 

The 2024 EPI found that many countries that were previously leading in sustainability goals have fallen behind or stalled, illustrating the challenges of reducing emissions in hard-to-decarbonize industries and resistant sectors such as agriculture. Over the last decade only five countries—Estonia, Finland, Greece, Timor-Leste, and the United Kingdom—have cut their GHG emissions at the rate needed to reach net zero by 2050.

Ephemeral streams affect water quality

Ephemeral streams, or those streams that flow only briefly after precipitation events, are a substantial pathway for water transfer with significant implications for water quality, a first-of-its-kind study coauthored by Yale researchers has found.

These streams—which transport water pollutants, sediments, and nutrients from land surfaces to rivers, lakes, reservoirs, and ultimately the oceans—influence a substantial amount of water output of the nation’s rivers, the researchers found. Following a 2023 US Supreme Court decision, however, they are no longer regulated by the Clean Water Act (CWA). “Our findings show that ephemeral streams are likely a substantial pathway through which pollution may influence downstream water quality, a finding that can inform evaluation of the consequences of limiting US federal jurisdiction over ephemeral streams under the CWA,” the researchers from Yale and the University of Massachusetts Amherst said in the study published in Science.