Phys.org
Historical rainfall and river flow data exist from only as far back as a few decades to 200 years, depending on the location time spans too short to assess long-term hydrological behavior accurately. Climate change adds more uncertainty, as historical data are less likely to correlate with potential future conditions. Tree ring widths, which reflect the dry or wet conditions affecting tree growth annually, provide valuable proxy climate data from before historical recordkeeping began. Click here to read the story. Click the following link for more information on Drought.