15,000 global scientists issue second 'warning to humanity'
Over 15,000 scientists from 184 countries have signed a letter called the "World Scientists' Warning to Humanity: A Second Notice," saying "catastrophic climate change" due to human influence has unleashed a "sixth mass extinction". Adding that most of the planet's problems are getting "far worse", the letter outlines 13 solutions which include a shift to renewable energy and population control.