Tag Archives: Science

Rivers bigger and more important that previously thought 2018-06-28

Rivers and streams cover more of the earth’s surface than previously thought, and likely interchange more CO2 and other gases with the atmosphere than previously thought. WWALS Science Committee Chair Tom Potter found this paper.

George H. Allen and Tamlin M. Pavelsky, Science, 28 Jun 2018, DOI: 10.1126/science.aat0636 Global extent of rivers and streams,

Abstract

The turbulent surfaces of rivers and streams are natural hotspots of biogeochemical exchange with the atmosphere. At the global scale, the total river-atmosphere flux of trace gasses such as CO2 depends on the proportion of Earth’s surface that is covered by the fluvial network, yet the total surface area of rivers and streams is poorly constrained. We used a global database of planform river hydromorphology and a statistical approach to show that global river and stream surface area at mean annual discharge is 773,000 ± 79,000 km2 (0.58 ± 0.06%) of Earth’s non-glaciated land surface, an area 44 ± 15% larger than previous spatial estimates. We found that rivers and streams likely play a greater role in controlling land-atmosphere fluxes than currently represented in global carbon budgets.

Fig. 1. Global River Widths from Landsat (GRWL) Database, Figure
Fig. 1. The Global River Widths from Landsat (GRWL) Database contains more than 58 million measurements of planform river geometry. The line plot on the right shows observed river coverage as a percentage of land area by latitude, and the bottom insets show GRWL at increasing zoom. The rightmost inset shows GRWL orthogonals over which river width was calculated, with only every eighth orthogonal shown for clarity.

You can see the lower Suwannee River in the above figure.

The authors zoom in on the Amazon River Basin in Brazil, but those last two zooms could easily be Continue reading →

High voltage DC evidence that solar and wind can make coal go away with no need for natural gas –WWALS to Suwannee BOCC 2016-02-01

Sent today to the Suwannee Board of County Commissioners (PDF):

Dear Commissioners,

It’s good to see you have a workshop about Sabal Trail’s proposed river crossings on the agenda for tonight. WWALS, including its members in Suwannee County, continues to oppose any such crossings of the Suwannee River or the Santa Fe River, or anywhere in the fragile karst terrain of central Florida and south Georgia containing our drinking water in the Floridan Aquifer.

Here’s more evidence that solar and wind can make coal go away with no need for natural gas. A new study shows adding interstate high-voltage DC electric power lines to load-balance across the U.S. would enable a very rapid shift to solar and wind power, dropping CO2 emissions by 80% from 1990 levels by 2030, five years from now. Florida needs to do its part by deploying solar power for local production during sunny days, rather than wasting $3 billion on yet another natural gas pipeline.

“Better power lines would help U.S. supercharge renewable energy, study suggests,” by Continue reading →