Oct 24, 2011

Has the magnitude of floods across the USA changed with global CO2 levels?

R. M. Hirsch and K.R. Ryberg
Hydrological Sciences Journal
  • Explores statistical relationships between annual floods at 200 long-term (85–127 years of record) streamgauges in the coterminous United States and the global mean carbon dioxide concentration (GMCO2) record
  • States that the streamgauge locations are limited to those with little or no regulation or urban development
  • Divides the coterminous US into four large regions and uses stationary bootstrapping to evaluate if the patterns of these statistical associations are significantly different from what would be expected under the null hypothesis that flood magnitudes are independent of GMCO2
  • Finds that in none of the four regions defined in this study is there strong statistical evidence for flood magnitudes increasing with increasing GMCO2
  • Finds that in one region, the southwest, there is a statistically significant negative relationship between GMCO2 and flood magnitudes