The 2019 Green Alliance Annual Debate discusses the ways in which earth observation and data science can improve our understanding of and ability to address environmental issues - for example, monitoring deforestation or water levels in reservoirs in real time through satellite images.

This book, by Jeremy Allouche, Carl Middleton and Dipak Gyawali, describes and critiques different understandings of the concept of the “nexus” between water, food and energy.

Growing millet next to a woody shrub native to West Africa could increase biomass by over 900% compared to growing millet alone, according to this paper. The shrub, Guiera senegalensis J.F. Gmel, has tap roots that can reach water deep in the soil. The study traced the movement of water from the shrub’s deep roots to the millet stems in a simulated drought.

The flooding caused by Hurricane Florence in North Carolina has drowned millions of chickens and thousands of pigs that were left on farms during the storm. The floodwaters have also caused at least 13 manure storage lagoons to overspill, spreading potentially dangerous bacteria and excess nutrients to the surrounding areas.

Farmers in Britain and other European countries have been affected by the ongoing heatwave and dry weather. Oxfordshire farmer Lesley Chandler told the Guardian, “It’s like a tinderbox out here… Just a spark could set it all alight” (read more here). Combine harvesters can create sparks if their blades hit a stone.

This paper surveys 195 cities in the United States and finds that the number of water conservation measures adopted in a city depend on both the climate (drier cities tend to have more water conservation measures than wetter cities) and political leanings (cities that lean towards the Democrats have more water conservation measures than Republican-leaning cities).

A project in Ladakh, India, creates “ice stupas”, a form of artificial glacier, to complement intermittent water flow from retreating natural glaciers. Water from streams is sprayed from vertical pipes during the winter, freezing into pointed mounds, which melt slowly throughout the year, irrigating crops in the summer.

Researchers from Nasa have used satellite data to identify areas where freshwater reserves have increased or decreased. The study found that in 14 regions, the changes were likely due to human factors (e.g. groundwater pumping), and in 8 areas, the changes were caused mainly by climate (e.g. drought or ice-sheet melting). Freshwater availability decreased in several areas including northern India, north-east China, the Caspian and Aral Seas and some of the Middle East.

In this TED talk, ocean expert Nancy Rabalais discusses the “dead zone” in the Gulf of Mexico - an area of the ocean where there isn’t enough oxygen to support sea life. Fertiliser runoff from farmland further up the Mississippi River is causing the dead zone, according to Rabalais. She says that solutions could include growing perennial grains and using precision fertilisation.