Could Doubling CO2 Increase Earth’s Temperature by 9 Degrees C?

by Emil Morhardt

That is the assertion of a paper in Nature by Carolyn W. Snyder (Snyder, 2016) based on an analysis of the correlation between atmospheric CO2 concentrations and changes in the global average surface temperature (GAST) over the past 800,000 years. Actually the assertion is that the 95% “credible interval” is 7 to 13 degrees Celsius (12.6 to 23 degrees Fahrenheit) Yikes! Even the current scientific consensus value of something on the order of 3 C (5.4 F) (Collins et al., 2013) is frightening when you consider that the difference in the GAST between the last glacial maximum about 20,000 years ago and at present wasn’t much different than that. Continue reading

Big Fish With a Bigger Problem: The Yellowtail Tuna Faces Difficulty in More Acidic Oceans

by Max Breitbarth

Anthropogenic emissions of carbon dioxide (CO2) have resulted in increased concentrations of CO2 in ocean waters that subsequently result in ocean acidification. Bromhead et al. (2015) explored the effects of elevated CO2 levels on the development of yellowfin tuna, Thunnus albacares in their March 2015 Deep-Sea Research article. Tuna represent some of the largest predators in the ocean, and cover vast expanses across several of the earth’s oceans—meaning the effects of ocean acidification could have ramifications for the species and their ecosystems around the world. The researchers found that ocean acidification levels have a strong negative effect on growth, hatch time, and larval survival in the experimental trials. These findings show that future ocean conditions may reduce the survivability of this fish in the future and lead to drastic marine ecosystem changes—as well as affect fishing practices by humans around the world that currently depend on yellowtail as a main source of food. Continue reading

Continuing Ocean Acidification Makes Finding Food Harder For Sharks

by Max Breitbarth

Anthropogenic emissions of carbon dioxide (CO2) have already directly affected corals, algae and other low-trophic level organisms in our oceans through the process of ocean acidification—the absorption of around 25% of atmospheric CO2 by the ocean. The increasing acidity has made forming calcified exoskeletons more difficult for corals, destroying localized ecosystems. The effects of a declining coral population have climbed up the food chain to threaten even predators near the top of the list. But what about the primary predators of the oceans…the feared, fascinating and ferocious sharks that have provided insight on marine feeding patterns, inspired tales like the one shown through the film Jaws, and are recognized by most as the biggest, baddest fish in the sea? Dixson et al. (2016) were interested in observing whether higher levels of ocean acidification sharks and rays, specifically their enhanced olfactory organs. Continue reading