In the central equatorial Pacific, all of CRW's 5km Regional Virtual Stations have decreased to Bleaching Watch or No Stress status. This includes the Samoas, which suffered multiple weeks of Alert Level 2 heat stress over the last few months, with confirmed reports of bleaching of both shallow and deeper corals.
The Main Hawaiian Islands (MHI), which observed record levels of bleaching in 2014 and static Alert Level 2 bleaching heat stress in October and November 2015, remain at a level of No Stress. The Northwestern Hawaiian Islands (NWHI), which sustained high, prolonged levels of bleaching heat stress in 2014 and some subsequent coral death, have elevated to a Bleaching Watch as of early July 2017. Alert Level 1 heat stress is now expected in the MHI and NWHI both in the next 9-12 weeks. CRW continues to collect data from field partners, including Hawai'i's Eyes of the Reef (EOR) volunteer community reef monitoring program, concerning the extent and severity of coral bleaching and mortality in the MHI and NWHI since 2014 and throughout the Third Global Coral Bleaching Event.
CRW's other 5km Regional Virtual Stations in Micronesia are all at a level of Bleaching Watch or higher again, after multiple regions, including the Republic of the Marshall Islands and the Eastern Federated States of Micronesia (FSM) registered Alert Level 2 bleaching heat stress for many weeks in early 2017. Alert Level 1 bleaching conditions are present in the Northern Mariana Islands and are expected to remain for the next 9-12 weeks. Severe Alert Level 2 heat stress is expected in Guam (which has been hit by severe bleaching four years in a row already) in the next 1-4 weeks. Alert Level 1 heat stress is also expected in the Western FSM and Eastern FSM in the next 1-4 weeks, and in Wake Atoll and the Marshall Islands in the upcoming 5-8 weeks.
In Micronesia's Phoenix Islands, in particular, as noted in multiple articles below and by numerous news outlets worldwide, in Kiribati, persistent elevated ocean temperatures (as high as 31.4-degrees Celsius) in 2015-2016 killed most of the corals in the region. Photos taken by scientists surveying the reef damage, especially around Kiritimati (Christmas Island), where more than 80% coral mortality has been documented, are gruesome. The high bleaching heat stress in Kiribati was tied to the very strong El Niño that dissipated in late 2016 but whose effects lasted for multiple additional months in the southern hemisphere. It is estimated that only 1-5% of Kiribati's reefs will survive and recover from this severe bleaching heat stress event.
Severe heat stress (Alert Levels 1 and 2) persisted for many weeks in East Asia in summer 2016, with significant coral bleaching being reported in multiple reef areas, including Hainan Island, China, Northern Vietnam, Dongsha, Taiwan, and in the Ryukyu Islands, Japan - where extensive (over 90%) bleaching was observed in the region's largest coral reef (Sekiseishoko Reef) as of July 2016, resulting in 70% mortality. Now, with Northern Hemisphere summer 2017 underway, a hopefully short-lived burst of Alert Level 1 bleaching heat stress is present again in the Northern Ryukyu Islands, Japan, Northern Taiwan, Hong Kong, China, and Hainan Island, China. Alert Level 1 heat stress is also expected again in Northern Vietnam in the next 1-4 weeks. CRW has been communicating with local coral reef management and research partners to determine the extent of the damage to the region's coral reefs during and since the Third Global Coral Bleaching Event.
In Southeast Asia, all of CRW's 5km Regional Virtual Stations are at a level of either Bleaching Watch or No Stress.
Coral bleaching heat stress is diminishing again throughout the Coral Triangle, although Sabah, Malaysia is currently experiencing a short burst of Alert Level 1 heat stress. CRW's five 5km Regional Virtual Stations for the Philippines have returned to a Bleaching Watch, after the Philippines suffered severe Alert Levels 1 and 2 heat stress for much of June and July 2017. CRW continues reaching out to local partners in the field to try and assess the status of local reefs of the Philippines and other areas of the Coral Triangle impacted by severe bleaching heat stress during and since the Third Global Coral Bleaching Event.
After multiple weeks of severe (Alert Levels 1 and 2) heat stress along much of the GBR, especially the central GBR, in March 2017 (the Reef's unprecedented, second consecutive year of confirmed mass bleaching), cooler waters finally arrived in the region in mid-April. All of CRW's 5km Regional Virtual Stations for the GBR region returned to a level of No Stress. CRW's near-real-time satellite monitoring and modeled predictions of environmental stress associated with the Third Global Coral Bleaching Event have been critical in helping local management and research partners plan effectual in-water and aerial surveys of the GBR, in both 2016 and 2017.
As of mid-May 2017, cooler waters had arrived along the western coast of Australia as well, in the Indian Ocean. All of CRW's 5km Regional Virtual Stations along Australia's west coast are at a level of Bleaching Watch or No Stress.
It is important to note, however that even though widespread coral bleaching was not confirmed throughout the Indian Ocean in the first half of 2017, in the Middle East, as of early July 2017, the Gulf of Oman is at Alert Level 1 heat stress. Alert Level 1 bleaching conditions are also expected in the Western Persian Gulf, Eastern Persian Gulf, Bahrain, Aden, Yemen, Western Yemen, Eritrea, Jazan, Saudi Arabia, the Sudan, Al Madinah and Makkah, and Egypt in the next 5-8 weeks; and in the Gulf of Oman (again), the Gulf of Tadjoura, Djubouti, the Gulf of Aqaba, Tabuk, Saudi Arabia, and the Gulf of Suez in 9-12 weeks' time.
In the Gulf of Mexico, heat stress in the Flower Garden Banks, Texas and Yucatan Peninsula dissipated in early November 2016. However, as of early July 2017, all three 5km Regional Virtual Stations for the Gulf region have elevated to Bleaching Watch status, with Alert Level 1 heat stress expected in 5-8 weeks' time.
A strong bleaching season in 2015 impacted coral reefs throughout the Caribbean. Bleaching of Caribbean corals at a number of reef locations (e.g., Cuba, the Turks and Caicos, the Bahamas, Haiti, the Dominican Republic, and Mexico) in 2015, as reported by partner organizations with divers working on affected reefs, including the XL Catlin Seaview Survey and Reef Check, led to NOAA's declaration of the Third Global Coral Bleaching Event on record (after the 1998 and 2010 global events). In early November 2016, high levels of bleaching heat stress returned to the eastern and southern portions of the Caribbean basin; these bleaching conditions remained until late December 2016. As of early July 2017, Alert Level 1 heat stress, present since mid-June, continues at the Columbia Atlantic and Panama Atlantic East 5km Regional Virtual Stations; this high heat stress is expected to remain for another 9-12 weeks' time. Alert Level 1 bleaching stress is expected to return to Costa Rica Atlantic, and Alert Level 2 heat stress is predicted again in Panama Atlantic West in the next 1-4 weeks. Alert Level 1 heat stress is then expected to arrive in Nicaragua, Honduras, Belize, and Quintana Roo, Mexico in the next 5-8 weeks, and to many of the 5km Regional Virtual Stations in the northerwestern Caribbean, including Cuba, the Cayman Islands, Jamaica, and Hispaniola in 9-12 weeks' time.
Click here to access the most recent Pacific Climate Update from NOAA CRW.
Climatic Background Conditions
As of April 2016 and
this writing, with NOAA's El Niño Advisory still in effect, the warming in the central to eastern tropical Pacific had begun to
dissipate, following the usual chronology of an El Niño. Importantly for some reefs, such as in Micronesia and Palau, a La Niña
Watch was in effect as the forecast estimated a >70% chance of a La Niña forming later this year.
2014: Initiation of the Global Bleaching Event
The current global coral bleaching event began in June 2014, with mass bleaching being first observed in Guam and the Commonwealth of the Northern Mariana Islands (CNMI, Heron et al. 2016a). This region is not normally linked to warming during an El Niño (Figure 1). However, the warming around Guam and the CNMI started a chain of large-scale warming events that propagated throughout the world's oceans and included the record-strength El Niño that peaked in late 2015. Elevated ocean temperatures lasted in Guam and the CNMI until October 2014. Regions of anomalously warm water then expanded until they merged with the southwestward extension of "The Blob", encompassing parts of the Hawaiian archipelago, where the most severe bleaching was seen at Lisianski Atoll in the Papaha̅naumokua̅kea Marine National Monument in September-October 2014. Thermal stress and bleaching also extended into the Main Hawaiian Islands where major bleaching was seen along windward Oahu, especially Ka̅ne´ohe Bay (Bahr et al. 2015). This was only the second widespread bleaching ever seen in the main islands of Hawai´i (Jokiel and Brown 2004). Also in September 2014, severe bleaching was documented in the Atlantic Ocean, in both southeastern Florida and the Florida Keys. In November, sustained high water temperatures in the Republic of the Marshall Islands resulted in their most severe bleaching ever reported (Fellenius 2014). NOAA Coral Reef Watch's 5-km Degree Heating Week values (Liu et al. 2014) exceeded 8 °C-weeks (categorized as Alert Level 2 thermal stress, associated with widespread coral bleaching and significant mortality) in many of these areas.
Figure 1. Coral Reef Watch Maximum Bleaching Alert Area map for September 2014. Marked are four areas exhibiting bleaching in the latter half of 2014. Alert Level 2 is associated with widespread coral bleaching and significant mortality.
January-June 2015: Bleaching Spreads
Initiation of the 2015-16 El Niño in mid-2015 resulted in high thermal stress in the eastern tropical Pacific, with observations of bleaching in Panamá, and expected but unconfirmed bleaching in the northern Galápagos Islands (Figure 4). Mid-2015 also brought thermal stress to Kiribati, especially the Line Islands (Figure 4).
Figure 2. Coral Reef Watch Maximum Bleaching Alert Area map for January-June 2015. Marked are six areas exhibiting bleaching in the first half of 2015.
Figure 3. Photo composite of before, during, and after bleaching at Airport Reef, Tutuila, American Samoa (image courtesy of R. Vevers, XL Catlin Seaview Survey).
July-December 2015: Global Bleaching
Unlike 2014, thermal stress and bleaching were widespread in the northern Caribbean, along with some bleaching in other parts of the basin. Bleaching of varying severity was reported in Florida, Cuba (northern and southern coasts), the Bahamas, Turks & Caicos, the Cayman Islands, parts of the Dominican Republic, Haiti, and Bonaire. Southeastern Florida and the Florida Keys not only saw a second year of bleaching, but southeastern Florida saw a severe outbreak of a white disease resulting in high levels of mortality.
As of October 2015, with widespread bleaching in each of the Indian, Pacific, and Atlantic basins, NOAA declared that the third documented global coral bleaching event was underway. This followed confirmed global bleaching in 1998 (Wilkinson 2000) and 2010 (Heron et al. 2016b). Of note, this actually may have been the fourth global event, as widespread, possibly global bleaching was seen in 1983 in association with the 1982-83 El Niño (Coffroth et al. 1990).
The El Niño continued to strengthen over the rest of 2015 and peaked in November-December 2015, becoming one of the strongest ever. By the end of 2015 32% of global coral reefs had been exposed to thermal stress of 4 °C-weeks or more and almost all of the world's reefs had exceeded their normal warm-season temperatures.
Figure 4. Coral Reef Watch Maximum Bleaching Alert Area map for 2015. Marked are five areas exhibiting bleaching in the latter half of 2015.
January-May 2016: Global Bleaching Continues
Figure 5. Coral Reef Watch Maximum Bleaching Alert Area map for January-May 2016. Includes list of marked areas with reports of severe bleaching.
Figure 6. Map of areas where 60% or more of the model ensemble members are predicting thermal stress at each of NOAA Coral Reef Watch's bleaching thermal stress alert levels through August 2016 (as of 3 May 2016).
To ensure documentation of the Third Global Coral Bleaching Event is as complete as possible, NOAA Coral Reef Watch continues collating data and information about and reporting on the global extent of this event. We are happy to work with any local or regional partners who plan to report on this event. Please assist us further by continuing to report coral bleaching and disease observations to your existing regional efforts, along with a brief email to email@example.com, or submit your reports directly to us at Coral Reef Watch. We still need both bleaching and non-bleaching observations to document the spatial extent and timing of the event, and for us to validate our satellite- and climate model-based products. Contributing data ensures that your site data are considered in global analyses; helps users understand how to better utilize the tools for your reefs; gives context to how bleaching patterns at your sites compare with global and regional patterns; and provides access to the latest global bleaching data analyses to communicate climate impacts to decision makers. All contributors will have the opportunity to co-author peer-reviewed publication(s) on global and/or regional bleaching that we are planning.
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Harvey, C (2015) Why dead coral reefs could mark the beginning of 'dangerous' climate change. The Washington Post, April 12, 2015. https://www.washingtonpost.com/news/energy-environment/wp/2016/04/12/why-dead-coral-reefs-stir-fears-of-dangerous-climate-change/.
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Heron SF, Eakin CM, Maynard JA, van Hooidonk R (2016b) Impacts and effects of ocean warming on coral reefs. In: Laffoley, D., & Baxter, J.M. (editors). 2016. Explaining ocean warming: Causes, scale, effects and consequences. Full report. Gland, Switzerland: IUCN. pp. 177-197. doi:http://dx.doi.org/10.2305/IUCN.CH.2016.08.en.
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Liu, G, Heron SF, Eakin CM, Muller-Karger FE, Vega-Rodriguez M, Guild LS, De La Cour JL, Geiger EF, Skirving WJ, Burgess TFR, Strong AE, Harris A, Maturi E, Ignatov A, Sapper J, Li J, Lynds S (2014) Reef-scale Thermal Stress Monitoring of Coral Ecosystems: New 5-km Global Products from NOAA Coral Reef Watch. Remote Sens. 6(11): 11579-11606, doi:10.3390/rs61111579.
Wilkinson, C (2000) Status of Coral Reefs of the World: 2000. Australian Institute of Marine Science, Townsville, Australia.