‘It’s death by a thousand cuts’: marine ecologist on the collapse of coral reefs – The Guardian

Tipping Points in Coral Reefs: A Critical Report on Marine Ecosystem Decline and Sustainable Development Goals

Introduction

David Obura, a Kenyan marine ecologist and chair of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), highlights the alarming decline of coral reefs worldwide. His expertise in coral ecosystems underscores the urgent need to address this environmental crisis, which directly impacts multiple Sustainable Development Goals (SDGs), including SDG 14 (Life Below Water), SDG 13 (Climate Action), and SDG 15 (Life on Land).

Importance of Coral Reefs

• Biodiversity Support: Coral reefs are home to vast biodiversity, providing essential food resources and environmental services.
• Coastal Protection: They act as natural buffers, protecting coastlines from storms and erosion.
• Ecosystem Architecture: Corals and their symbiotic algae function similarly to underwater forests, maintaining ecosystem complexity and health.

These roles align with SDG 14, which aims to conserve and sustainably use the oceans, seas, and marine resources.

Current Status and Threats to Coral Reefs

1. Environmental Changes: Climate change and pollution alter the environmental conditions necessary for coral survival, contributing to reef degradation.
2. Overexploitation: Fishing and other human activities reduce reef biomass, weakening ecosystem interactions.
3. Loss of Biodiversity: Approximately 50% of live coral area has been lost, diminishing species diversity and abundance.

This degradation threatens the achievement of SDG 14 and SDG 12 (Responsible Consumption and Production) by undermining sustainable marine resource management.

Understanding Tipping Points in Coral Ecosystems

Tipping points refer to critical thresholds where coral reef systems lose their defining characteristics, such as species diversity and ecosystem functions. Crossing these points results in ecosystem collapse, effectively ending the existence of coral reefs.

Indicators of Reef Collapse

• Reduction in vibrant colors due to coral and invertebrate loss, replaced by drab algae.
• Decline in fish abundance and diversity, leading to quieter underwater soundscapes.
• Breakdown of the three-dimensional reef structure within approximately a decade.

Geographical Variations in Reef Health

The “Coral Triangle” in the Indonesian-Philippine region remains relatively resilient, though local threats persist. In contrast, regions such as the Caribbean and Persian-Arabian Gulf exhibit severe declines, with some areas no longer qualifying as coral reefs. These regional disparities highlight the need for targeted conservation efforts, supporting SDG 14 and SDG 11 (Sustainable Cities and Communities) by protecting coastal environments.

Proximity to Global Tipping Points

Local tipping points have been surpassed in many reefs globally. The Caribbean region may have reached a regional tipping point, with all assessed coral reef regions classified as threatened on the red list of ecosystems. Without effective intervention, ecosystem collapse within 50 years is highly probable.

Climate Change and Coral Reef Resilience

• Revised temperature thresholds indicate coral reefs can withstand global warming between 1°C and 1.5°C above preindustrial levels.
• The world is approaching or has possibly exceeded this threshold due to cumulative greenhouse gas emissions.

This situation underscores the critical importance of SDG 13 (Climate Action) to limit global warming and protect marine ecosystems.

Consequences of Coral Reef Loss

1. Loss of coral reef physical structures and biodiversity.
2. Reduced coastal protection, increasing vulnerability to storms.
3. Decline in fish populations that support food security and livelihoods.
4. Economic impacts on fisheries and tourism-dependent communities.

The loss of coral reefs threatens SDG 1 (No Poverty), SDG 2 (Zero Hunger), and SDG 8 (Decent Work and Economic Growth) by undermining natural capital and economic foundations.

Impact on Fish Species

Fish species dependent on coral reefs, including small ornamental fish and a broader diversity of species feeding on algae and plankton, are adversely affected by reef degradation. This impacts marine biodiversity conservation efforts aligned with SDG 14.

Absence of Positive Offsets

Coral loss leads to algae dominance, which may temporarily increase herbivorous fish but ultimately results in ecosystem simplification and decline. No redeeming ecological impacts have been observed, emphasizing the urgency of conservation.

Broader Societal Impacts

• Psychological: Loss of natural beauty and biodiversity affects human well-being and cultural experiences.
• Economic: Declines in fisheries and tourism affect global and local economies.
• Environmental Warning: Coral reefs serve as indicators (“canaries in the coalmine”) for broader climate and ecological tipping points.

These factors relate to SDG 3 (Good Health and Well-being) and SDG 10 (Reduced Inequalities) by highlighting the interconnectedness of environmental health and human societies.

Restoration Efforts and Challenges

Current coral restoration techniques show promise but are limited in scale and effectiveness due to environmental stressors such as warming, pollution, and overextraction. Restoration efforts primarily serve to engage communities and raise awareness, fostering commitment to conservation aligned with SDG 17 (Partnerships for the Goals).

Technological Solutions and Equity Considerations

While scientific research into artificial coral growth continues, there is concern regarding the allocation of resources. Priority should be given to community development and resilience, particularly in low-income regions, ensuring equitable benefits and adherence to SDG 10 and SDG 16 (Peace, Justice, and Strong Institutions).

Call to Action

David Obura emphasizes the responsibility of high-income consumers and economies to reduce their environmental footprints. Transformative actions in the global north are essential to enable sustainable futures and prevent further coral reef decline, supporting the comprehensive achievement of the SDGs.

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Tipping Points: On the Edge? – A Series on Our Future

This report is part of a series exploring critical tipping points in Earth’s systems, including the Amazon rainforest and Antarctic regions. The series examines the latest scientific insights and their implications for global sustainability.

Read more about tipping points and their global impact.

1. Sustainable Development Goals (SDGs) Addressed in the Article

1. SDG 14: Life Below Water
   • The article focuses extensively on coral reefs, their decline, and the impact on marine biodiversity, which directly relates to SDG 14 aiming to conserve and sustainably use the oceans, seas, and marine resources.
2. SDG 13: Climate Action
   • Climate change is identified as a major factor causing coral reef degradation and tipping points, linking the article to SDG 13 which calls for urgent action to combat climate change and its impacts.
3. SDG 15: Life on Land
   • The article mentions biodiversity loss and ecosystem services, which are also relevant to SDG 15 that focuses on protecting, restoring, and promoting sustainable use of terrestrial ecosystems and biodiversity.
4. SDG 12: Responsible Consumption and Production
   • The article highlights the role of high-income consumers and economies in driving environmental degradation, implying the need for sustainable consumption patterns as targeted by SDG 12.
5. SDG 1: No Poverty
   • The article discusses the impact of coral reef loss on coastal communities and low-income populations, linking to SDG 1 which aims to end poverty in all its forms.

2. Specific Targets Under the Identified SDGs

1. SDG 14: Life Below Water
   • Target 14.2: Sustainably manage and protect marine and coastal ecosystems to avoid significant adverse impacts, including restoring them to achieve healthy and productive oceans.
   • Target 14.3: Minimize and address the impacts of ocean acidification, including through enhanced scientific cooperation at all levels.
2. SDG 13: Climate Action
   • Target 13.1: Strengthen resilience and adaptive capacity to climate-related hazards and natural disasters in all countries.
   • Target 13.2: Integrate climate change measures into national policies, strategies, and planning.
3. SDG 15: Life on Land
   • Target 15.5: Take urgent and significant action to reduce the degradation of natural habitats, halt the loss of biodiversity, and protect endangered species.
4. SDG 12: Responsible Consumption and Production
   • Target 12.2: Achieve the sustainable management and efficient use of natural resources.
   • Target 12.8: Ensure that people everywhere have the relevant information and awareness for sustainable development and lifestyles in harmony with nature.
5. SDG 1: No Poverty
   • Target 1.5: Build resilience of the poor and those in vulnerable situations to climate-related extreme events and other economic, social, and environmental shocks and disasters.

3. Indicators Mentioned or Implied in the Article to Measure Progress

1. Coral Cover and Health
   • Percentage of live coral cover remaining (article states half of live coral area has been lost).
   • Measures of coral reef biodiversity and abundance of fish and invertebrates.
   • Indicators of reef complexity such as three-dimensional structure.
2. Climate Change Metrics
   • Global temperature rise relative to pre-industrial levels (article mentions tipping points between 1°C and 1.5°C warming).
   • Frequency and intensity of climate-related hazards affecting marine ecosystems.
3. Ecosystem Threat Levels
   • Red List of Ecosystems status for coral reef regions indicating risk of collapse within 50 years.
4. Socioeconomic Indicators
   • Economic impacts on fisheries and tourism dependent on coral reefs.
   • Measures of community resilience and local livelihoods affected by coral reef degradation.
5. Awareness and Engagement
   • Public engagement in coral restoration efforts and conservation commitment.
   • Information dissemination on sustainable consumption and environmental impacts.

4. Table of SDGs, Targets, and Indicators

SDGs	Targets	Indicators
SDG 14: Life Below Water	14.2: Sustainably manage and protect marine and coastal ecosystems. 14.3: Minimize and address ocean acidification impacts.	Percentage of live coral cover. Biodiversity and abundance of marine species. Reef structural complexity.
SDG 13: Climate Action	13.1: Strengthen resilience and adaptive capacity to climate hazards. 13.2: Integrate climate change measures into policies.	Global temperature increase relative to pre-industrial levels. Frequency of climate-related hazards affecting reefs.
SDG 15: Life on Land	15.5: Reduce degradation of natural habitats and halt biodiversity loss.	Red List of Ecosystems status for coral reef regions.
SDG 12: Responsible Consumption and Production	12.2: Sustainable management and efficient use of natural resources. 12.8: Ensure awareness for sustainable development and lifestyles.	Public engagement in conservation efforts. Information dissemination on environmental impacts.
SDG 1: No Poverty	1.5: Build resilience of poor and vulnerable to climate and environmental shocks.	Economic impacts on coastal communities dependent on reefs. Measures of community resilience and livelihood security.

Source: theguardian.com