Query: describes a world of worsening food shortages and wildfires, and a mass die-off of coral reefs as soon as 2040

Relevant passages:
Drought <=SEP=> A drought is a period of below-average precipitation in a given region , resulting in prolonged shortages in its water supply , whether atmospheric , surface water or ground water . A drought can last for months or years , or may be declared after as few as 15 days . It can have a substantial impact on the ecosystem and agriculture of the affected region and harm to the local economy . Annual dry seasons in the tropics significantly increase the chances of a drought developing and subsequent bush fires . Periods of heat can significantly worsen drought conditions by hastening evaporation of water vapour .   Many plant species , such as those in the family Cactaceae ( or cacti ) , have drought tolerance adaptations like reduced leaf area and waxy cuticles to enhance their ability to tolerate drought . Some others survive dry periods as buried seeds . Semi-permanent drought produces arid biomes such as deserts and grasslands . Prolonged droughts have caused mass migrations and humanitarian crises . Most arid ecosystems have inherently low productivity . The most prolonged drought ever in the world in recorded history occurred in the Atacama Desert in Chile ( 400 Years ) .

Coral bleaching <=SEP=> Coral bleaching occurs when coral polyps expel algae that lives inside their tissues . Normally , coral polyps live in an endosymbiotic relationship with the algae and that relationship is crucial for the coral and hence for the health of the whole reef . Bleached corals continue to live . But as the algae provide the coral with 90 % of its energy , after expelling the algae the coral begins to starve . Above-average sea water temperatures caused by global warming have been identified as a leading cause for coral bleaching worldwide . Between 2014 and 2016 , the longest global bleaching events ever were recorded . According to the United Nations Environment Programme , these bleaching events killed coral on an unprecedented scale . In 2016 , bleaching hit 90 percent of coral on the Great Barrier Reef and killed 29 percent of the reef 's coral . In 2017 , the bleaching further expanded to areas of the park that were previously spared , such as the central one .   __ TOC __

Great Barrier Reef <=SEP=> The Great Barrier Reef is the world 's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2300 km over an area of approximately 344400 km2 . The reef is located in the Coral Sea , off the coast of Queensland , Australia .   The Great Barrier Reef can be seen from outer space and is the world 's biggest single structure made by living organisms . This reef structure is composed of and built by billions of tiny organisms , known as coral polyps . It supports a wide diversity of life and was selected as a World Heritage Site in 1981 . CNN labelled it one of the seven natural wonders of the world . The Queensland National Trust named it a state icon of Queensland .   A large part of the reef is protected by the Great Barrier Reef Marine Park , which helps to limit the impact of human use , such as fishing and tourism . Other environmental pressures on the reef and its ecosystem include runoff , climate change accompanied by mass coral bleaching , and cyclic population outbreaks of the crown-of-thorns starfish . According to a study published in October 2012 by the Proceedings of the National Academy of Sciences , the reef has lost more than half its coral cover since 1985 .   The Great Barrier Reef has long been known to and used by the Aboriginal Australian and Torres Strait Islander peoples , and is an important part of local groups ' cultures and spirituality . The reef is a very popular destination for tourists , especially in the Whitsunday Islands and Cairns regions . Tourism is an important economic activity for the region , generating over AUD$ 3 billion per year . In November 2014 , Google launched Google Underwater Street View in 3D of the Great Barrier Reef .   A March 2016 report stated that coral bleaching was more widespread than previously thought , seriously affecting the northern parts of the reef as a result of warming ocean temperatures . In October 2016 , Outside published an obituary for the reef ; the article was criticized for being premature and hindering efforts to bolster the resilience of the reef . In March 2017 , the journal Nature published a paper showing that huge sections of a 800-kilometre ( 500 mi ) stretch in the northern part of the reef had died in the course of 2016 due to high water temperatures , an event that the authors put down to the effects of global climate change .

Effects of global warming on human health <=SEP=> The effects of global warming include effects on human health . The observed and projected increased frequency and severity of climate related impacts will further exacerbate the effects on human health . This article describes some of those effects on individuals and populations .

Wild fisheries <=SEP=> A fishery is an area with an associated fish or aquatic population which is harvested for its commercial value . Fisheries can be marine ( saltwater ) or freshwater . They can also be wild or farmed .   Wild fisheries are sometimes called capture fisheries . The aquatic life they support is not controlled in any meaningful way and needs to be `` captured '' or fished . Wild fisheries exist primarily in the oceans , and particularly around coasts and continental shelves . They also exist in lakes and rivers . Issues with wild fisheries are overfishing and pollution . Significant wild fisheries have collapsed or are in danger of collapsing , due to overfishing and pollution . Overall , production from the world 's wild fisheries has levelled out , and may be starting to decline .   As a contrast to wild fisheries , farmed fisheries can operate in sheltered coastal waters , in rivers , lakes and ponds , or in enclosed bodies of water such as tanks . Farmed fisheries are technological in nature , and revolve around developments in aquaculture . Farmed fisheries are expanding , and Chinese aquaculture in particular is making many advances . Nevertheless , the majority of fish consumed by humans continues to be sourced from wild fisheries . As of the early 21st century , fish is humanity 's only significant wild food source .