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Mixed news for the Great Barrier Reef

August 27, 2024 By EarthWise Leave a Comment

A prolonged and widespread coral bleaching event in Australia’s Great Barrier Reef has taken place this year. It is the fifth such event over the past eight years and appears to be one of the worst ever. According to preliminary analysis, 97% of corals in some areas of the northern part of the reef died as a result of the bleaching. Over the entire length of the reef – which is more than 1,200 miles long – bleaching was observed on 74% of the more than 1,000 individual reefs that make up the Great Barrier Reef. Half of those observed recorded high or very high levels of bleaching, although less than 10% had extreme levels of bleaching.

Prior to this mass bleaching event, an extensive survey of the reef was conducted, and it provided some good news. Coral cover had increased in all three regions on the Great Barrier Reef and was actually at regional highs in two of the three regions. The surveys were completed before the passage of Tropic Cyclone Jasper in December 2023.

Bleached corals are very stressed, but they still remain alive for at least some period of time. Some types of corals can remain bleached for months, hanging on like a hospital patient in critical condition, but then recover. Depending upon water conditions going forward, it remains to be seen how much of the reef will survive the latest bleaching event. The next survey season by the Australian Institute of Marine Science will commence in September.

In many ways, the reef has had some lucky escapes in recent years. As marine heatwaves become increasingly common, its luck may eventually run out.

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New report on Great Barrier Reef shows coral cover increases before onset of serious bleaching, cyclones

Photo, posted 8, 2023, courtesy of Chris Hoare via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

July Was A Scorcher | Earth Wise

September 2, 2021 By EarthWise Leave a Comment

July 2021 has the unfortunate distinction as being the world’s hottest month ever recorded according to global data from the National Oceanic and Atmospheric Administration. July is typically the warmest month of the year, but this July was the warmest month of any year on record.

The combined global land and ocean surface temperature was 62.07 degrees Fahrenheit, which is 1.67 degrees above the 20th century average. This was the highest monthly average since records began 142 years ago. It broke the previous record set in July 2016 and tied in 2019 and 2020.

The Northern Hemisphere was 2.77 degrees above average. Asia had its hottest July on record. Europe had its second hottest July on record. Places like Africa, Australia, and New Zealand all had top-ten warmest Julys.

Other aspects of the changing climate included the observation that Arctic sea ice coverage for July was the fourth-smallest in the 43-year record. Interestingly, Antarctic sea ice extent was actually above average in July. Global tropic cyclone activity this year so far is above normal for the number of named storms. In the Atlantic basin, the formation of the storm Elsa on July 1 was the earliest date for a 5th named storm.

It remains very likely that 2021 will rank among the 10 hottest years on record. Extreme heat is a reflection on the long-term climate changes that were outlined recently in a major report released by the Intergovernmental Panel on Climate Change. These latest global observations add to the disturbing and disruptive path that the changing climate has set for the world.

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It’s official: July was Earth’s hottest month on record

Photo, posted July 15, 2021, courtesy of Lori Iverson/National Interagency Fire Center via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

2018 Was A Wet Year

March 20, 2019 By EarthWise Leave a Comment

Recent news reports noted that 2018 was the fourth hottest year on record. But the changing climate is not just about temperature. 2018 was also the third-wettest year since 1895, when steady record-keeping began.

Overall, the U.S. recorded 4.68 inches more precipitation in 2018 than the 20th century average. But all that rain and snow was nothing like evenly distributed. The eastern half of the country – especially in places like North Carolina and Virginia – saw record amounts of precipitation, while most of the West remained stuck in drought.

The warming climate leads to precipitation extremes at both ends, meaning that wet places are likely to get wetter and dry places drier. There has been a marked upward trend in short-duration extreme events. For example, Cyclone Mekunu dumped almost 13 inches of rain on Salalah, Oman in 36 hours, more than double its annual average rainfall.

In the southeast and eastern U.S., the trend toward stronger storm events is mostly driven by strong warming of the oceans that fringe their shores. Warm oceans evaporate more water into the air and warm air holds more water than cooler air. Warmer, moisture-laden air acts like a blanket over the land, keeping heat trapped near the ground. Many of the states that had their wettest-ever years also set records for high minimum temperatures – their coldest temperatures were less cold than in the past.

Air temperatures are projected to warm up even further in the coming years and, as a result, many scientists are anticipating that extreme precipitation events will only get more extreme. The pattern of drought in the west and wetness in the east is likely to stay.

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2018 was the U.S.’s third-wettest year on record—here’s why

Photo, posted August 18, 2018, courtesy of Jim Lukach via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.