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With global warming and melting ice, it isn’t easy being a polar bear anymore. Some studies have predicted that polar bears could very well be extinct by the end of the century. The good news is not all researchers think the bears are absolutely doomed. Scientists at the American Museum of Natural History (AMNH) have published a new paper indicating that things might not be as bleak for polar bears as their peers expect.

For 25 years, methodical research by scientists has investigated the effects of the Exxon Valdez oil spill in 1989 on Alaskan communities and ecosystems. A new study released today into the effects of the 1989 Exxon Valdez oil spill in Alaska shows that embryonic salmon and herring exposed to very low levels of crude oil can develop hidden heart defects that compromise their later survival, indicating that the spill may have had much greater impacts on spawning fish than previously recognized.

The herring population crashed four years after the spill in Prince William Sound and pink salmon stocks also declined, but the link to the oil spill has remained controversial. The new findings published in the online journal Scientific Reports suggest that the delayed effects of the spill may have been important contributors to the declines.

Like the leaves of New England maples, phytoplankton, the microalgae at the base of most oceanic food webs, photosynthesize when exposed to sunlight. In the process, they absorb carbon dioxide from the atmosphere, converting it to carbohydrates and oxygen. Many phytoplankton species also release dimethyl sulfide (DMS) into the atmosphere, where it forms sulfate aerosols, which can directly reflect sunlight or increase cloud cover and reflectivity, resulting in a cooling effect. The ability of phytoplankton to draw planet-warming carbon dioxide (CO2) from the atmosphere and produce aerosols that promote further cooling has made ocean fertilization — through massive dispersal of iron sulfite and other nutrients that stimulate phytoplankton growth — an attractive geoengineering method to reduce global warming.

Sea level rise poses one of the biggest threats to human systems in a globally warming world, potentially causing trillions of dollars' worth of damages to flooded cities around the world. As surface temperatures rise, ice sheets are melting at record rates and sea levels are rising.

But there may be some good news amid the worry. Sea levels may not rise as high as assumed.

Los tomadores de decisiones costeras deben alejarse de la consideración de las fuerzas físicas y económicas de manera aislada para reconocer completamente, y explicar, los cambios en las costas, según una nueva investigación de la Universidad de Cardiff.