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Global coral bleaching

May 22, 2024 By EarthWise Leave a Comment

The world’s coral reefs are in the midst of a global bleaching event being driven by extraordinarily high ocean temperatures. This is the fourth such global event on record and is predicted to be the largest one ever. Coral bleaching occurs when corals are stressed by heat and eject the symbiotic algae within them that they need to survive. Bleached corals can recover if water temperatures cool soon enough. Otherwise, they die.

Each of the three previous coral bleaching events has been worse than the last. The first, in 1998, affected 20% of the world’s reefs. The second, in 2010, affected 35%. The third, from 2014 to 2017, affected 56% of reefs.

The current bleaching event was confirmed by satellite observations early in April and was already seen to be affecting more than half of the world’s coral areas across the Pacific, Indian, and Atlantic Oceans. The ongoing event is expected to be the worst bleaching ever experienced by Australia’s Great Barrier Reef. A small saving grace is that the current bleaching event is not expected to be of extremely long duration because the El Niño in the Pacific has abated.

Coral bleaching events are becoming more severe and frequent due to increased marine heat waves driven by climate change. Last year was particularly difficult for corals as global sea temperatures reached record high levels for several months.

Widespread coral bleaching impacts economies, livelihoods, food security, and more. Coral reefs provide ecosystem services essential to marine life and human populations as well. Global action will be needed for coral interventions and restorations.

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Satellites watch as 4th global coral bleaching event unfolds

Photo, posted March 23, 2012, courtesy of Oregon State University via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cutting The Cost Of Energy Storage | Earth Wise

September 9, 2021 By EarthWise Leave a Comment

The cost of both solar and wind power continues to drop making the two renewable energy sources the cheapest way to make electricity in more and more places. Given the virtually inexhaustible supply of both wind and sun power, these clean electricity sources can in principle meet all our energy needs. The hang up is that both of them are intermittent sources – the wind doesn’t blow all the time and the sun doesn’t shine all the time.

The solution to the intermittency problem is energy storage. If energy produced by wind and sun can be stored so it can be made available for use at any time, then the goal of having 100% clean energy can be realized.

Energy storage technology has continued to improve over time and to get cheaper. The Department of Energy recently announced a new initiative aimed at accelerating both of these trends.

The new program – called Long Duration Storage Shot – has the goal of reducing the cost of grid-scale, long-duration energy storage by 90% within this decade.

Long-duration energy storage is defined as systems that can store energy for more than ten hours at a time. Such systems can support a low-cost, reliable, carbon-free electric grid that can supply power even when energy generation is unavailable or lower than demand. With long-duration storage, solar-generated power can be used at night.

The program will consider multiple types of storage technologies – electrochemical (that is: batteries), mechanical, thermal, chemical carriers, and various combinations thereof. Any technology that has the potential to meet the necessary duration and cost targets for long-term grid storage are fair game for the program.

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DOE announces goal to cut costs of long-duration energy storage by 90%

Photo, posted October 16, 2017, courtesy of UC Davis College of Engineering via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Dolphins

May 27, 2019 By EarthWise Leave a Comment

We don’t think of heatwaves as something that affects the ocean, but increasingly, as the planet warms, there have been instances where ocean water temperatures become much higher than normal for extended periods of time. There has been much discussion of this phenomenon with regard to coral reefs where the catastrophic rise in coral bleaching events has been the result.

Recently, a study at the University of Zurich looked at the effects of ocean heatwaves on marine life higher in the food chain. They studied the well-known dolphin population in Shark Bay, Western Australia.

In early 2011, a heatwave caused water temperatures in Shark Bay to rise more than 4 degrees above the annual average for an extended period. This led to a substantial loss of seagrass, which is a driving factor in the Shark Bay ecosystem.

The researchers investigated how this environmental damage affected survival and reproduction of dolphins, using long-term data on hundreds of animals collected over a ten-year period from 2007 to 2017.

Their analysis showed that dolphins’ survival rate dropped by 12% and female dolphins were giving birth to fewer calves. That phenomenon that began in 2011 lasted at least until 2017.

The researchers were surprised by the extent and the duration of the influence of the heatwave, especially the fact that the reproductive rate of dolphins had not returned to normal even after 6 years.

This study shows for the first time that marine heatwaves not only affect organisms at the lower levels of the food chain, but also might have considerable long-term consequences for the animals at the top, such as dolphins.

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Climate change is a threat to dolphins’ survival

Photo, posted December 14, 2014, courtesy of Ed Dunens via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.