Nearly every day brings news about climate change and its impacts, from wildfires in Greenland to melting ice on Antarctica to Europeans sweating through record-high summer temperatures. These stories, plus urgent warnings about rising sea levels and record amounts of greenhouse gases, can foster strong impulses to “do something.”
One of the first jobs, though, is to know the problem—and fortunately, today’s photonics researchers have risen to the call to quantify global climate and environmental change. From wind to ice, from treetops to coral reefs, today’s most sophisticated optical instruments are examining the condition of humanity’s home planet.
Photonic sensing of Earth’s environment falls into three broad categories. Laser ranging excels in quantifying how solids—such as ice sheets—increase or decrease in elevation. Hyperspectral imaging gathers full spectral data from each pixel in an image, revealing patterns of healthy and diseased life forms in their habitats. And, thanks to advances in portability, laser spectroscopy can fill in some crucial gaps in our knowledge of the distribution of problematic atmospheric gases. Many technologies work both for day-to-day weather sensing for meteorological models, and for tracking and assessment of longer-term climate trends.