Save our corals!

"If you get people diving on a coral reef, they're going to become more respectful of the outdoors and more concerned with the threats that place faces" - Tim Cahill, Australian Athlete

One of the best things I did on my gap year was learn to dive; breathing underwater and being surrounded by a vast array of organisms in a coral reef is an unforgettable experience. However global warming is making these environments a rarity.

Figure 1: Cartoon displaying the effects of increased sea temperatures on the underwater environment - Source: Steve Sack

What causes coral bleaching and ocean acidification?

The ocean has absorbed approximately 30% of all carbon dioxide released by anthropogenic activity since 1800's. The uptake of co2 decreases the ph of ocean water as it is converted to carbonic acid, placing coral reefs at extreme risk. Reef building corals and calcifying algae use carbonate to produce the calcium carbonate skeletons which build the reefs. Hydrogen ions released by carbonic acid bind to calcium carbonate, decreasing its concentration and form bicarbonate changing the ocean chemistry affecting the process of calcification, consequently affecting coral reef growth. 

Ocean acidification also effects crucial reef building animals through weakening their calcium carbonate shells, and changes ecosystem dynamics. Furthermore, ocean acidification is reported to a bleaching agent for corals.

Video 1: Dr. Triona McGrath explains how the oceans are changing due to ocean acidification and how it will impact the marine life 

 Coral bleaching is mainly caused by warmer ocean temperatures. When water is too warm, corals expel zooxanthellae causing them to turn completely white. Upon bleaching, the coral isn't necessarily dead, but it is under more stress and is more likely to die.  Mass coral bleaching events are directly related to my previous post about the El Niño-Southern Oscillation event.

Video 1: Explains the process of coral bleaching in more depth

Figure 2: Table highlighting the effects of many Climate variables and their influence on coral bleaching, specifically reiterating my point about ENSO  - Source: Great Barrier Reef Marine Park Authorities

Video 2: 360-degree video showing the extent of coral bleaching in the Great Barrier Reef - Source: Climate Central 

Ocean acidification and Pacific reefs

Ocean acidification is extremely far reaching and effects many aspects of the environment; corals being one of them. By 2034, a 5% decrease in calcification is predicted for all reefs as a result of decreases in ph of 0.06 units per decade in the tropical Pacific. Ocean acidification is predicted to have important socioeconomic and ecological implications for the region including damage to fisheries, tourism and ecosystems.

Coral bleaching globally and the pacific

Coral bleaching is becoming a more frequent occurrence and now more than 70% of coral reefs globally have experienced heat stress potentially leading to bleaching or mortality. 

Figure 4: Map highlighting all the coral bleaching events globally between 1979 and 2010 - Source: Chumkiew, Jaroensutasinee and Jaroensutasinee, 2011

Video 3: Displays the severity of coral bleaching globally

The Pacific Ocean's temperature has increased by 0.31 degrees since the 1950s. Currently, 50% of Pacific reefs are classified as threatened and 20% were highly threatened. This figure is due to rise to 90% by 2030. By geographic region, the eastern pacific region has experienced the most bleaching, while Micronesia, Melanesia and Polynesian reefs the least. Furthermore, bleaching events are projected to become more frequent in the future, with prediction suggesting, they could occur annually in Micronesia by 2040.

Figure 5: Highlights the extent of bleaching in the pacific between the 9th of November and today! - Source: NOAA

Figure 6: The current threat to coral reefs in the Pacific region - Source:  Status on Coral Reefs of the Pacific and Outlook 2011

The Coral Triangle

The Western Pacific is known as the 'Coral Triangle' which comprises of the Solomon Islands, Papua NewGuinea, Timor Leste and several Asian countries. The region is a marine biodiversity hotspot containing 75% of all known coral species and provides shelter for 40% of the world's reef fish.

Figure 7: Map of the Coral Triangle - Source: Hossain et al., 2016

Figure 8: Coral Triangle atlas interactive map! Very interesting tool, please have a play! - Source:http://ctatlas.reefbase.org/atlas/default.aspx?layers=8,68,24&zoom=4&lat=7.46260404298648&lng=125.86914062500001&maptype=terrain

The Coral Triangle Initiative (CTI)

The CTI is a multilateral agreement among six nations to protect a global biodiversity hotspot regarding its coral reefs, fisheries and food security . The region is approximately 5.7 million Km² and directly supports the livelihoods and food security of 100 million people. Additionally, commercial fisheries alone provide USD 3 billion annually to the regional economies, highlighting its great importance.

Figure 9: Map displaying all 612 marine protected areas within the Coral Triangle - Source: Venegas-Li et al 2016

Figure 10: Goals and targets of the Coral Triangle Initiative, many of which will improve the effects of social issues caused by global warming in the Pacific Islands involved - Source: Berdej, Andrachuk and Armitage, 2015

Why is coral so important?

1.  Reefs only make-up 1% of the world's marine environments, but they provide a home for 25% of marine species 
2.  A decrease in the number of coral reefs saw over 75% of reef fish species decline, 50% of which decreased to less than half of their original number
3. Pacific islands have a strong dependence on fishing with fish being an important source of protein
4. Coral reefs reduce wave energy by 97% which would otherwise impact the shoreline
5. Provide substantial economic benefit through tourism and exports
6. Medicinal purposes

Mitigation techniques

A number of techniques have been developed to reduce the effects of coral bleaching 

• Shading of coral
• Connecting coral reefs 
• Building coral tolerance to bleaching
• Marine protected areas 
• 3D printed corals
• Microfragmentation

Figure 11: Diagram displaying coral bleaching mitigation techniques, many of which, particularly the "support human adaptive capacity" and "protect resistance" sections relate directly to the goals of the coral triangle initiative - Source: NOAA

Corals reefs in the Pacific are extremely important to everyday life, through providing sustenance, economic benefits and protection. Our moral obligation as global citizens to protect planet provide further reasoning as to why we should protect these natural phenomena globally as well as in the Pacific for future generations to enjoy!

Wells

Forecast = Extreme?

"The record-breaking extreme weather events causing chaos across the globe should be a wake-up call" - Christiana Figueres, Executive Secretary of the UNFCC

I'm not sure about you, but I always complain about the weather in London, but i've come to realise I don't really have much to complain about. One of the main problems of climate change in the Pacific is extreme weather events and storm surges which result in large-scale humanitarian emergencies. 

Figure 1: Cartoon displaying scientist scrambling to find solutions and adaptations to extreme weather AKA cyclone Pam in the South Pacific - Source: David Pope

What causes extreme weather in the South Pacific?

The main cause of the variable climate and extreme weather in the South Pacific is the El Niño Southern Oscillation (ENSO) Phenomenon. ENSO is the scientific term that describes the fluctuations in temperature between the ocean and atmosphere in the Pacific. ENSO has three states, two of which are opposites, "El Niño" and "La Niña".  

Video 1: Explains the effects of ENSO and what causes it 

Intensified ENSO due to global warming has affected the weather in the region dramatically resulting several coinciding processes. Tropical cyclones (TC) generate elevated coastal sea levels through storm surges and high waves.  TCs reportedly account for 76% of natural disasters in the region and the number of very intense cyclones is due to increase in the South Pacific. As a result of the low-lying nature of Pacific Islands, these TCs have catastrophic consequences. 

Figure 2: Tracks of the approximately 2,400 tropical cyclones in the Pacific region in the last 60 years - Source: The World Bank

Figure 3: Flow diagram showing how global warming has caused intensified the impacts of ENSO - Source: Walsh, McInnes, McBride., 2012

Droughts in the region are strongly influenced by La Niña.  Many Pacific Islands are reliant on rainwater for domestic and agricultural use. The lack of water is extremely detrimental to the region affecting many aspects of life.

Examples of extreme weather events in the South Pacific 

Cyclone Pam

Cyclone Pam was the one of the strongest TC to form in the south Pacific Ocean with winds of 250 km/h peaking at 320 km/h. The category five storm hit the region extremely hard causing damage to most islands.

Figure 4: Map showing the path of tropical cyclone Pam - Source: Encyclopaedia Britannica

Figure 5: Damage caused to some Pacific islands - Source: The World Bank

Vanuatu is considered the most at risk nations in the world to natural disasters and was destroyed by cyclone Pam. It affected approximately 250,000 people and reduced economic activity by 111% in the country.

Figure 6: Economic cost of cyclone Pam to Vanuatu - Source: The World Bank

Vanuatu received aid from a number of countries, especially Australia who contributed to help rebuild Vanuatu considerably.

Video 2: News clip displaying the damage done by Cyclone Pam in the Pacific 

2011 Pacific drought

In 2011, the South Pacific experienced a severe drought affecting a number of countries across the region, but none more so than Tuvalu. Tuvalu is fully reliant on rainwater for domestic usage and typically receives 200-400mm of rainfall per month (Quite a lot!). 

Figure 7: Location of Tuvalu - Source: Treehugger

Video 3: News clip displaying the problems of drought and water shortage in Tuvalu

Mitigation techniques

A number of different techniques are used to reduce the impacts on Pacific islands, these include:

Figure 8: Summary of coping strategies to disasters and climate changes, with traditional food security, coping and governance techniques proving to be the most successful - Source: Fletcher et al., 2013


Extreme weather events are completely out of the Pacifics control and I feel more should be done to help the nations prepare for these catastrophes. 

Wells

Where is Noah's Ark? We need it

"The sea is certainly common to all" - Plautus 

I have returned to normality from my master's application sabbatical to find UCL ranked 28th in the UK environmental university ranking! Only makes me prouder to study at such a well-rounded institution. In previous post's I explained the causes of sea level rise (SLR) and in this post, I thought I'd put global SLR into perspective.

Figure 1: Statue of Liberty going for a swimming  

Global mean SLR has increased from 2.2 +/- 0.3 mm yr^-1 to 3.3 +/- 0.3mm yr^-1 in 21 years, this increase has had profound effects worldwide. Some countries possess longer coastal lines than others and therefore the potential effects vary between regions.  In the following paragraphs, I will highlight the regional differences in SLR.

Figure 2: An interactive map displaying the length of every countries coastline

Europe

In Europe, approximately 19% of the entire population are estimated to live within 10km of a coastline and 75% of people in the Mediterranean live in coastal areas. By 2100, extreme SLR on European coastlines is projected to reach 57cm under Representative concentration pathways (RCP) 4.5 and 81 cm under RCP8.5. While mean SLR is expected to be 53cm and 77cm under the same pathways. The Black sea and the Atlantic are thought be worst hit, with towns such as Esbjerg in Denmark experiencing 106cm of SLR.

Figure 3: Absolute sea level rise across Europe between 1992-2014 - Source: European Environment Agency

Figure 4: The effects of 60 meters sea level rise in Europe - Source: Data for Minds

Video 1: Explains what Europe would like if all the ice melted on earth

North America

SLR is becoming an ever-greater problem in North America. SLR in the region of 90cm by 2100 will put the land of 4.2 million people under risk of inundation. While SLR of 180cm will affect 13.1 million people. SLR in the northwest Atlantic is estimated to be 5.3 +/- 2.6 mm/y  which is relatively low compared to the Pacific.

Figure 5: Schematic showing the US population living less than 3.3 feet above sea level - Source: Union of Concerned Scientists

Video 2: Shows how islands in Canada are experiencing very similar effects to those seen in the Pacific in terms of shoreline erosion, SLR and issues surrounding water supply

Figure 6: The effects of 60 meters sea level rise in North America - Source: Data for Minds

South America

Currently only 6% of the South American population live in low-elevation coastal zones, however this is thought to increase dramatically with population growth (Find out more about the effects of population on climate change on my friends blog). Estimates suggest by 2050 8.9 million inhabitants will be effected by inundation, damaging USD819 billion in built capital.  Cities such as Rio and Lima are expected to experience SLR of 14cm. Furthermore, the ice melt in Patagonia is thought to contribute considerable to SLR.

Figure 7: Schematic displaying the cities at risk of sea level rise in South America 

Asia

The effects of SLR in Asia are potentially enormous. Globally, the continent has the highest concentration of people in low lying coastal zones. SLR is very high near the Philippines at approximately 14.7 +/- 4.39 mm/y and Indonesia at  8.3 +/- 1.53 mm/y. 

Video 3: Explains what Asia would look like if all the ice on earth melted

Figure 8:  Schematic displaying the cities at risk of sea level rise in Asia - Source: UN Habitat Global Urban Observatory 2008

Africa

Approximately 56 million people live in low elevation across 320 coastal cities in Africa. A mid-range scenario of 43cm rise by 2100 would flood 16 million people's homes and 10 million people would be forced to migrate causing damages worth $38 billion.

Figure 9: Schematic displaying the cities at risk of sea level rise in Africa - Source: UN Habitat Global Urban Observatory 2008

Video 4: Explains the problems associated with SLR in West Africa

Although SLR is a serious global problem, it is undoubtedly worse in the Pacific, where whole populations and islands will disappear. In my next post, I will explain how the South Pacific compares!

Wells