A previously unknown species of extinct dwarf sperm whale has been described for the first time. The whale, which lived around six million years ago, had a highly asymmetrical skull and a distinctly downward-curving head – features that helped it adapt to its environment. 

In the earth sciences – and beyond – Iran and Afghanistan have a certain iconic status as largely inhospitable areas, rich in raw materials. But where does this remarkable geology come from? Researchers from the University of Central Asia and Utrecht University have now reconstructed the history of this 'geological Silk Road' in detail. "Culturally, the region lies at the crossroads of European, Central Asian, East Asian, Indian and Arab influences. Our reconstruction shows that the same is true geologically." Their results are published in the scientific journal Gondwana Research.

Removing carbon dioxide from the atmosphere is considered necessary alongside emissions reductions, but proposed removal approaches differ in their storage duration, energy requirements, cost and potential scale. Enhanced weathering applies finely ground silicate rock to soils, increasing the mineral surface available to react with carbon dioxide and form dissolved carbon compounds. The approach could store carbon over long timescales, but its performance depends on rock chemistry, weather, soil conditions and the emissions generated by mining, grinding, transport and spreading. Assessing these factors together is important because a large theoretical capacity does not by itself establish how much carbon a deployment would remove net of its own emissions.

Authors Li Ruan, Jianwu Li, Zhaoliang Song, and colleagues from the Zhejiang Academy of Agricultural Sciences, Zhejiang A & F University, and Tianjin University assessed enhanced-weathering potential using a global silicate-rock dataset of 9,088 records. The study compared basalt, peridotite and granitoid using theoretical carbon-sequestration potential and weathering indices, then evaluated basalt’s distribution and life-cycle carbon footprint. The authors modeled 50-year outcomes for particles of 10, 37, 100 and 1,000 μm across different pH conditions, incorporating estimates of process energy and emissions. They also assessed cropland suitability globally using temperature, precipitation and soil-pH data.

Understanding the sources and quantities of carbon dioxide (CO₂) released to the atmosphere is central to assessing past emissions and identifying potential reductions. Fossil fuel combustion is the principal source of human-caused CO₂ emissions, alongside emissions from natural gas flaring and venting and the manufacture of cement. Consistent estimates across countries and years help distinguish changes in emissions from changes in data coverage or accounting methods. The CDIAC-FF dataset provides annual estimates reaching back to 1750 and records emissions by fuel type and, for recent decades, economic sector.

Authors Michael Erb and Gregg Marland from the Research Institute for Environment, Energy and Economics at Appalachian State University updated the CDIAC-FF dataset through 2022. The research describes a data product, using United Nations Statistics Division energy data for fuel production, trade and consumption from 1950 onward, with earlier estimates drawn from historical sources. The authors estimate emissions using both a reference approach based on apparent national fuel use and a sectoral approach based on consumption by economic sector. The inventory covers fossil fuel use, natural gas flaring and venting, and cement production, with national and global estimates kept within consistent accounting boundaries over time.

A Riverine Carbon Source

Rivers connect terrestrial, oceanic, and atmospheric carbon pools while processing carbon and nitrogen that can be released as greenhouse gases. Carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) fluxes vary widely among rivers because of differences in land cover, hydrology, water quality, and microbial activity. Large watersheds remain difficult to assess because studies often focus on isolated headwater or human-impacted reaches rather than the full flow path.

The Yarlung Tsangpo is a transboundary river on the Tibetan Plateau and the longest river on the plateau, spanning glaciers, pastures, agricultural areas, urban zones, forests, and narrow gorges. Authors Guoliang Li, Jason Feijian Mao, and colleagues from the Chinese Academy of Sciences, Lanzhou Jiaotong University, and the Tibetan Ecology and Environment Monitoring Center investigated dissolved organic matter (DOM) characteristics and greenhouse-gas emissions across the river and its tributaries. They sampled 32 sites in September 2024, measured water quality and CO₂, CH₄, and N₂O fluxes, and conducted a second campaign in May 2025 at four representative sites using ultraviolet–visible spectroscopy, excitation-emission matrix spectroscopy, and Fourier-transform ion cyclotron resonance mass spectrometry.