12/04/2025: Water demand consistently overestimated in California

Featured Research 

Californian water suppliers consistently overestimate water demand
A study of 61 water suppliers in California found that projections of water demand from 2000 to 2020 consistently overestimated actual demand — by 25% for five-year projections and by 74% for 20-year projections, on average. Water demand per capita, which suppliers typically assumed to be stable or growing, dropped nearly 2% per year over the study period. Researchers attribute this to an increase in rebate programs and mandatory regulations for limiting outdoor water use. As climate change makes water conservation more uncertain, they write, water suppliers should improve forecasting methods to avoid needless infrastructure costs and support sustainable water management. [Water Resources Research study] 

Record heat coming to these three world regions
Experts expect climate change to bring more extreme humid heat to many parts of the world, enough to approach the limits of human tolerance in some places — yet regional-level humid heat events have received little attention from scientists and the media. Looking at record humid-heat days from 216 regions around the world, researchers used climate models to assess the odds of those records getting broken under today’s climate conditions. They identified the eastern United States, eastern China, and much of Australia as particularly likely to see humid heat more extreme than in recent decades, highlighting these regions as potentially underprepared. [AGU Advances study] 

Using 400 years of Chinese historical records to project epidemics
Comparing weather records from the Ming and Qing dynasties in China, researchers examined the role extreme weather like floods and droughts played in epidemics. They found the impact was regional with the largest correlation between drought specifically and large-scale epidemics gradually decreases from northern China down to southern China. Additionally, epidemics historically had at least 32 years between outbreaks. [GeoHealth study] 

Climate change makes combined cyclone-heatwaves worse for coastal China
As climate change progresses, tropical cyclones and heatwaves increasingly occur back-to-back, exacerbating the damage either event would have on its own. Climate model simulations indicate that in a future with continued high emissions of greenhouse gases, China’s densely populated southeastern coast will likely experience stronger, broader, more frequent, and longer-lasting tropical cyclone-heatwaves, with temperatures 2°C warmer than 1980-2010 summer conditions. Researchers call for improved early warning systems and urban heat mitigation efforts to protect vulnerable populations in the region. [JGR Atmospheres study] 

Climate variations in tropical oceans drive primarily extreme events
Severe droughts and floods are primarily driven by climate variations in tropical oceans, with interannual and decadal patterns playing key roles. [Eos editors’ highlight][AGU Advances study] 

Heatwaves increase home births in India
Heatwaves in India are associated with increased home births, with differential susceptibilities across regions and populations, threatening maternal and newborn health. [Eos editors’ highlight][GeoHealth study]