Guardian: At a meeting in Ottawa, Canada, this week, Barack Obama, Justin Trudeau, and Enrique Peña Nieto will commit to a plan to have the US, Canada, and Mexico produce half their electricity from hydropower, wind, solar, and nuclear plants by 2025. That represents a large increase from the current collective clean power levels of about 37%. The agreement will also include plans for carbon capture and storage and energy efficiency measures. Because the US accounts for 75% of the three countries’ energy production and only one third of its production is from clean energy, it will have the most work to do to reach the stated goal. A Supreme Court ruling earlier this year halted Obama’s attempt to reduce coal plant emissions to meet emissions targets set at the 2015 Paris climate conference. Although Mexico currently produces less than 20% of its electricity from clean sources, Canada gets 81% of its power from renewables.
Modeling the shapes of tree branches, neurons, and blood vessels is a thorny problem, but researchers have just discovered that much of the math has already been done.