Essential Reads

Invasive species – including plants, animals and fish – cause heavy damage to crops, wildlife and human health worldwide. Some prey on native species; other out-compete them for space and food or spread disease. A new United Nations report estimates the losses generated by invasives at more than US$423 billion yearly and shows that these damages have at least quadrupled in every decade since 1970. Humans regularly move animals, plants and other living species from their home areas to new locations, either accidentally or on purpose. For example, they may import plants from faraway locations to raise as crops or bring in a nonnative animal to prey on a local pest. Other invasives hitch rides in cargo or ships’ ballast water. When a species that is not native to a particular area becomes established there, reproducing quickly and causing harm, it has become invasive. These recent articles from The Conversation describe how several invasive species are causing eco...

Humans rely on the ocean for many things, including food, jobs, recreation and stabilization of Earth’s climate. But although ocean resources may seem infinite, human impacts like pollution, overfishing and climate change are creating what United Nations Secretary-General António Guterres has called an “ocean emergency.” Climate change is pushing ocean temperatures to record levels, many fisheries are overharvested, and plastic waste is accumulating in the deep sea. These five articles from The Conversation’s archive spotlight urgent challenges for ocean conservation, and describe what researchers are doing to devise effective responses. 1. A devastating invasion is expanding Invasive lionfish are aggressive predators, native to the Indo-Pacific Ocean, that feed on smaller reef fish. They have caused heavy damage in the Caribbean and Gulf of Mexico since they first appeared in the Atlantic in 1985. Now, they’ve spread south to Brazil, which ha...

A 23-year western drought has drastically shrunk the Colorado River, which provides water for drinking and irrigation for Wyoming, Colorado, Utah, New Mexico, Arizona, Nevada, California and two states in Mexico. Under a 1922 compact, these jurisdictions receive fixed allocations of water from the river – but now there’s not enough water to provide them. As states try to negotiate ways to share the decreasing flow, the U.S. Department of the Interior is considering cuts of up to 25% in allotments for California, Nevada and Arizona. The federal government can regulate these states’ water shares because they come mainly from Lake Mead, the largest U.S. reservoir, which was created when the Hoover Dam was built on the Colorado River near Las Vegas. These five articles from The Conversation’s archive explain what’s happening and what’s at stake in the Colorado River basin’s drought crisis. The Colorado River prov...

Reading the latest international climate report can feel overwhelming. It describes how rising temperatures caused by increasing greenhouse gas emissions from human activities are having rapid, widespread effects on the weather, climate and ecosystems in every region of the planet, and it says the risks are escalating faster than scientists expected. Global temperatures are now 1.1 degree Celsius (2 degrees Fahrenheit) warmer than at the start of the industrial era. Heat waves, storms, fires and floods are harming humans and ecosystems. Hundreds of species have disappeared from regions as temperatures rise, and climate change is causing irreversible changes to sea ice, oceans and glaciers. In some areas, it’s becoming harder to adapt to the changes, the authors write. Still, there are reasons for optimism – falling renewable energy costs are starting to transform the power sector, for example, and the use of electric vehicles is expanding. But change aren’t hap...

The U.S. Environmental Protection Agency is preparing to release a draft regulation limiting two fluorinated chemicals, known by the abbreviations PFOA and PFOS, in drinking water. These chemicals are two types of PFAS, a broad class of substances often referred to as “forever chemicals” because they are very persistent in the environment. PFAS are widely used in hundreds of products, from nonstick cookware coatings to food packaging, stain- and water-resistant clothing and firefighting foams. Studies show that high levels of PFAS exposure may lead to health effects that include reduced immune system function, increased cholesterol levels and elevated risk of kidney or testicular cancer. Population-based screenings over the past 20 years show that most Americans have been exposed to PFAS and have detectable levels in their blood. The new regulation is designed to protect public health by setting an enforceable maximum standard limiting how much of the two target ch...