Inhabitat's Week in Green: trains speed up, paint improves planes, and the CO2-scrubbing artificial trees

Each week our friends at Inhabitat recap the week's most interesting green developments and clean tech news for us -- it's the Week in Green.

This week Inhabitat saw high-speed railways pick up steam around the globe as China announced plans to build a trans-continental railroad in South America and Japan began developing the world's fastest high-speed train. We also saw eco transportation reach new heights as a kite-powered car completed an epic 5,000km journey across Australia and researchers developed a nanotech paint that will increase the fuel efficiency of airplanes. The automotive world is also gearing up for the Geneva car show as Toyota is getting set to roll out an all-electric IQ and Porsche pulled back the curtain on its Panamera S Hybrid and Boxster EV.

In other news, this week we brought you an exclusive video interview where celebrated environmentalist Stewart Brand argues that nuclear power could save the world. We also explored several other alternative energy sources that are decidedly less controversial - PurposeEnergy is transforming beer brewing waste into a source of clean-burning biofuel, and a design duo has proposed a series of beautiful solar-powered artificial trees that scrub CO2 from the air.

Roughly one in every six people do not have access to safe drinking water, so we were excited to learn about a pedal-powered water purification system based on the bicycle that holds great promise for the developing world. Speaking of cleaning up dirty water, this week Stephen Baldwin sued Kevin Costner over the oil-separating technology that cleaned up the BP oil spill. And last but not least, we were wowed by this hydrofloor system, which can save space and energy by concealing a swimming pool beneath your living room floor!