Climate Change
How Is The Maldives Affected?

Working with Global News Resources

Introduction

Anthropogenic (human-induced) climate change is the greatest threat the world has ever faced. The atmosphere and oceans are currently warming at an unprecedented rate, and coral reefs are one of the planet’s most vulnerable ecosystems to the impacts of global warming.

Corals depend on algae (zooxanthellae) for their nutrients. The zooxanthellae live inside the coral tissue, giving corals their characteristic colours. In exchange for safe lodgings, the zooxanthellae provide nutrients to the corals produced through photosynthesis. Warming oceans and increased solar irradiance damage the photosynthetic system of the zooxanthellae, causing the zooxanthellae to overproduce oxygen. The resultant toxicity leads the corals to expel the zooxanthellae leaving their calcium carbonate skeleton exposed. This phenomenon is known as coral bleaching.

  • During short periods of elevated temperatures, corals can appear temporarily pale-coloured and bleached, and are then able to re-uptake zooxanthellae. (But during this period, with insufficient nutrients and exposed skeletons, they are more vulnerable to disease and parasites).
  • Prolonged periods of elevated temperatures (exacerbated by sunny days), will eventually kill the corals after accumulated thermal stresses (measured in “degree heating weeks”). Dead corals are easily identifiable, as they soon become covered in marine algae.

Mass coral bleaching events coincide with warmer temperatures, making coral reefs particularly vulnerable to global warming. Across the world, including in the Maldives, mass coral bleaching events have resulted in mass coral mortality, seen particularly in recent years – 1998, 2010, and 2016. You can read our detailed hands-on monthly illustrated reports on the 2016 bleaching event in the Maldives in our Reefscapers Diaries series.


The Inevitable Climatic Catastrophe

Over the past 30 years, more than half the greenhouse gases ever generated have been unleashed into the atmosphere. The planet is already +1.2°C above baseline, with a further +1°C likely in the next decade.

Escalating temperatures will further disrupt weather systems, amplifying the frequency and intensity of extreme weather events, from storms and floods to hurricanes, wildfires and prolonged droughts.

Ultimately, planet Earth itself will recover, but humanity must create a sustainable future before it’s too late. Confronting the magnitude of our ecological crisis, we need prompt, collective action to avert global catastrophe.

  • Temperatures increase – regions become uninhabitable, crops fail, sparking mass migration.
  • Biodiversity collapse – the Amazon, oceanic phytoplankton, insect apocalypse (our food supply) …
  • Inequalities – climate change disproportionately affects developing countries and indigenous peoples.
  • Global water crisis – demand for fresh water outstrips supply by 40%, as soon as 2030.
  • Rising methane emissions – thawing permafrost accelerates environmental degradation.
  • Pandemics – human encroachment destroys wilderness, increasing the risk of zoonotic diseases.
  • Plastics – endocrine disruptors threaten reproductive health on a global scale.
  • Global dimming paradox – high levels of industrial aerosols have been mitigating the sun’s heat.
  • Coastal regions – heavily populated regions face inundation by storms, wave surges and floods.
  • Sea level rise – low lying island nations, including the Maldives, are particularly at risk.
    Coral reefs and climate change: wave‐driven flooding of tropical coastlinesQuataert (2015)
    Atolls will soon be uninhabitable: sea-level rise & wave-driven floodingStorlazzi et al (2018)
    Impact of Sea-Level Rise on Pacific Marshall Islands – Storlazzi et al (2017) PDF – U.S. Geological Survey
NASA Global Ocean Circulation (AMOC)

NASA: Slowdown of the Motion of the Ocean – AMOC collapse
A simplified illustration of the global “conveyor belt” of ocean currents that transport heat around Earth.

Useful Long-Term Resources

September 2023

The Earth’s Climate System is Out of Energy Balance

The relatively steady temperature of the Earth is maintained by a fine balance between incoming radiation from the sun, and outgoing heat radiation to space. The global warming story has always centred on green house gases blocking outgoing heat radiation. But in recent decades, the absorbed incoming solar radiation has been exceeding the outgoing heat radiation to space, and by large amounts. As confirmation, this top-of-atmosphere satellite data matches the ocean heat uptake (measured by robotic diving buoys). Many thanks to @Gergyl for the concise summary.

Why does it matter? The net inward radiation flux is not only trending higher, but also accelerating. Just 2 watts per square metre spread over the whole Earth’s surface [510 million km2] is the equivalent of 1 trillion electric radiators operating continuously.

Where does all this energy go? Into heating the atmosphere and the land surface, into evaporating more water, and into melting ice, but mostly into heating up the oceans (because the thermal capacity of water is very high.) 93% of the energy has been heating the shallow oceans (down to 300m depth).

So where is this increasing incoming radiation coming from? It is not due to increased solar output (apart from a minor 11-year cycle). The Earth is absorbing more sunlight due to reduced reflection:
– reduced sea ice and cloud cover,
– less atmospheric aerosols (particulates) from fossil fuel burning, including S02 from shipping.
– scientists continue to analyse data & discuss these factors relative to each other.

Global Ocean Heat Content (GOHC): rate of change (with uncertainty estimates).
GCOS Minière et al (2023) – Robust acceleration of Earth system heating observed over the past six decades

2024.01 NATURE Global ocean heat content - Rate of change

Heat stored in the Earth system 1960–2020: where does the energy go? Schuckmann et al (2023)

The Earth’s climate is out of energy balance, and this study quantifies how much heat has consequently accumulated over the past decades (ocean: 89%, land: 6%, cryosphere: 4%, atmosphere: 1%).
Since 1971, this accumulated heat reached record values at an increasing pace. The Earth heat inventory provides a comprehensive view on the status and expectation of global warming, that needs to be included in the Paris Agreement’s Global Stocktake.

Trend in Earth’s Energy Imbalance (2024) Hodnebrog et al
Reduction in man-made particles had to be accounted for (orange line) so the models matched actual satellite measurements (black line).
Recent cleanup of air pollution has led to reductions in emissions of tiny particles (aerosols). Satellite measurements show more heat enters the Earth’s atmosphere from the Sun compared to terrestrial energy escaping to space, leading to accumulation of heat and warming of the Earth’s surface. Man-made greenhouse gases have been the major cause of global warming, but air particle pollution has masked part of this warming by reflecting sunlight and cooling the planet.
“Continued reductions of particle emissions may lead to an accelerated surface temperature warming already in this decade.” — Hodnebrog

December 2023

2023.12.28 climate reanalyzer
Temperature anomaly 2m

NOAA: Restoring ‘Seven Iconic Reefs’ to save Florida’s coral reefs

An unprecedented, decades-long approach to restore reefs in Florida’s National Marine Sanctuary

Launch (Dec 2019): Florida’s $100 million coral propagation project: Official project page

BUT … After mass coral die-off, Florida scientists rethink plans – and – archived version

Ocean temperatures rose to unprecedented levels in July 2023, fueled by calm, hot weather tied to El Niño and boosted by climate change. By September 2023, many areas endured 20+ weeks of elevated ocean temperatures (+1°C above average, during the hottest month of the year), causing a mass coral die-off.

There is no final estimate of casualties of artificially planted corals at the ‘Seven Iconic Reefs’, but a survey in August 2023 showed 30% of the staghorn and 45% of the elkhorn was already dead, and 90% was bleaching.
By late September … no living elkhorn or staghorn (was found). Similar damage was observed through much of the Caribbean at both natural and restored reefs.

 

FORECAST 2024

Met Office 2024 global temperature forecast
SST Forecast Jan-Aug 2024

Global SST Forecast Jan-Aug 2024

StarTalk: “How 2023 Broke Our Climate Models”
– with Neil deGrasse Tyson & Gavin Schmidt

Global SST Forecast Jan-Aug 2024

“I wasn’t worried about climate change. Now I am”
– science communicator Dr Sabine Hossenfelder