Risks of ‘domino effect’ of tipping points greater than thought, study says

Scientists warn policymakers not to ignore links, and stress that ‘every action counts’

The authors said their paper, published in the journal Science, highlights how overstressed and overlapping natural systems are combining to throw up a growing number of unwelcome surprises.

The study collated existing research on ecosystem transitions that can irreversibly tip to another state, such as coral reefs bleaching and being overrun by algae, forests becoming savannahs and ice sheets melting into oceans. It then cross-referenced the 30 types of shift to examine the impacts they might have on one another and human society.

Only 19% were entirely isolated. Another 36% shared a common cause, but were not likely to interact. The remaining 45% had the potential to create either a one-way domino effect or mutually reinforcing feedbacks.

A woman scuba diving over bleached coral on the Great Barrier Reef
 The destruction of coral reefs can weaken coastal defences and expose mangrove forests to damage. Photograph: Greg Torda/ARC Centre of Excellence for Coral Reef Studies

Among the latter pairings were Arctic ice sheets and boreal forests. When the former melt, there is less ice to reflect the sun’s heat so the temperature of the planet rises. This increases the risks of forest fires, which discharge carbon into the air that adds to the greenhouse effect, which melts more ice. Although geographically distant, each amplifies the other.

By contrast, a one-way domino-type impact is that between coral reefs and mangrove forests. When the former are destroyed, it weakens coastal defences and exposes mangroves to storms and ocean surges.

The deforestation of the Amazon is responsible for multiple “cascading effects” – weakening rain systems, forests becoming savannah, and reduced water supplies for cities like São Paulo and crops in the foothills of the Andes. This, in turn, increases the pressure for more land clearance.

Until recently, the study of tipping points was controversial, but it is increasingly accepted as an explanation for climate changes that are happening with more speed and ferocity than earlier computer models predicted. The loss of coral reefs and Arctic sea ice may already be past the point of no return. There are signs the Antarctic is heading the same way faster than thought.

Co-author Garry Peterson said the tipping of the west Antarctic ice shelf was not on the radar of many scientists 10 years ago, but now there was overwhelming evidence of the risks – including losses of chunks of ice the size of New York – and some studies now suggest the tipping point may have already been passed by the southern ice sheet, which may now be releasing carbon into the atmosphere.

“We’re surprised at the rate of change in the Earth system. So much is happening at the same time and at a faster speed than we would have thought 20 years ago. That’s a real concern,” said Peterson. “We’re heading ever faster towards the edge of a cliff.”

The fourth most downloaded academic research of 2018 was the Hothouse Earth paper, which considered how tipping points could combine to push the global climate into an uninhabitable state.

The authors of the new paper say their work goes beyond climate studies by mapping a wider range of ecological stress points, such as biodiversity loss, agricultural expansion, urbanisation and soil erosion. It also focuses more on what is happening at the local level now, rather than projecting geo-planetary trends into the future.

“We’re looking at things that affect people in their daily lives. They’re things that are happening today,” said Peterson. “There is a positive message as it expands the range of options for action. It is not just at an international level. Mayors can also make a difference by addressing soil erosion, or putting in place social policies that place less stress on the environment, or building up natural coastal defences.”

Rocha has spent 10 years building a database of tipping points, or “regime shifts” as he calls them. He urges policymakers to adopt a similar interdisciplinary approach so they can better grasp what is happening.

“We’re trying to connect the dots between different research communities,” said Rocha. “Governments also need to look more at interactions. They should stop compartmentalising ministries like agriculture, fisheries and international relations and try to manage environmental problems by embracing the diversity of causes and mechanisms underlying them. Policies need to match the scale of the problem.

“It’s a little depressing knowing we are not on a trajectory to keep our ecosystem in a functional state, but these connections are also a reason for hope; good management in one place can prevent severe environmental degradation elsewhere. Every action counts.”


The new data follows a World Meteorological Organization report from November that found atmospheric concentrations of the top three greenhouse gases driving global warming—carbon dioxide, methane, and nitrous oxide—have hit record high levels, which provoked warnings that “without rapid cuts in CO2 and other greenhouse gases, climate change will have increasingly destructive and irreversible impacts on life on Earth.”


1. The IPCC Report Provided The World With Some Dire Warnings

In October, the Intergovernmental Panel on Climate Change (IPCC), a UN body dedicated to reporting climate change science to the world, released its Fifth Assessment Report.

The report warned global leaders that capping global warming to 1.5C above pre-industrial temperatures would require unprecedented changes and a reduction in global greenhouse gas emissions to zero by 2050.

The IPCC report outlined the stark differences between a 1.5C rise in global surface temperature and a 2C rise in global impact in terms of droughts, flooding, sea level rise, species extinction, famine and extreme weather events.

2. Climate Change Is Going To Have Huge Effects On Human Health

The medical journal The Lancet has been tracking the impact of climate change on health since 2015 through its Countdown project.

The 2018 report outlined how medical professionals around the world are increasingly being forced to respond to challenges directly related to climate change.

The authors detail how rapidly changing global temperatures are increasing heatwaves, infectious diseases and risk of declining food security.

The report states that as the planet continues to heat up, 51% of cities internationally will lose the security of their public health infrastructure.

The Countdown 2018 report also notes that air pollution from coal fired power plants contributes to 460,000 deaths each year.

3. The UN Emissions Gap Report Told Us That Nations Are Not Slowing Greenhouse Gas Emissions As Much As They Need To

The annual report released by UN Environment investigates global trends of greenhouse gas emissions and compares these to rates that the world should be abiding by to avoid the worst consequences of climate change.

The emissions gap is calculated by comparing each nation’s commitments to lowering greenhouse gas emissions against a projection of their emissions trends.

The 2018 emissions gap has grown compared to previous reports and the authors of the report stated that in order to limit global warming to 1.5C above pre-industrial temperatures, total global emissions must be more than halved.

The report also stated that only six of the world’s 20 largest economies are on track to achieve their Paris Climate Agreement commitments to reduce greenhouse gas emissions.

Those not on track include Argentina, Australia, Canada, the European Union, Korea, Saudi Arabia, South Africa and the United States.

4. 60 Countries Were Officially Ranked On Their Performance For Slowing Climate Change

The Climate Change Performance Index (CCPI) for 2019 was released in December.

The report rates countries on their adherence to cutting down greenhouse gas emissions, using renewable energy sources, overall energy use and development of climate policy.

Sweden, Morocco, Lithuania, Latvia and the United Kingdom were ranked as the top five countries.

As has become tradition with the CCPI, however, the top three positions were left vacant to signify that no nation has truly achieved an optimal attitude towards climate change action.

The bottom five countries were Taipei, Korea, Iran, the United States and Saudi Arabia.

5. A Report Found That 2017’s Hurricane Harvey Was Made Worse By Climate Change

Hurricane Harvey hit in 2017 and it was the first major hurricane to make landfall in the United States in 12 years.

Harvey was the first in a series of destructive storms that struck the Caribbean and southern United States in the 2017 storm season, causing some US$125 billion in damage.

An estimated 13 million people were affected by the storm and 88 were killed.

study published in May of this year, led by Dr Kevin E. Trenberth from the National Center for Atmospheric Research in the US, directly linked Harvey’s destructive power to higher ocean heat content and sea surface temperature caused by climate change.

The report states that Harvey could not have caused so much flooding “without human-induced climate change” and that vulnerable areas must prepare for “supercharged hurricanes” with contingency plans such as evacuation routes and power cuts.

Mattgush / Getty Images

6. Storm Categories Need To Upgrade To A Category 6, According To A NASA Researcher

Timothy Hall, a senior scientist at the NASA Goddard Institute for Space Studies, proposed that the Saffir-Simpson categorisation of storms, which currently ranges from category 1 to category 5, needs to expand to include category 6 storms.

This suggestion was supported by a number of climate scientists who agreed that hurricane strength and rains will be increased in a warmer climate.

A category 5 storm includes storms with winds of 157 miles per hour (252 kilometres per hour) or more but Hall stated that storms with wind speeds of 230 miles per hour (370 kilometres per hour) could occur by the end of the century.

Mikemareen / Getty Images

7. Humans Are Using The Earth’s Resources Much Faster Than The Earth Can Keep Up With

Earth Overshoot Day is calculated by the Global Footprint Network and provides a date every year by which humanity has consumed resources and emitted carbon at a pace that the Earth can renew over the course of a year.

In 2018, the date was the earliest ever estimated: August 1.

In 1970 the date was calculated to be in late December and by 1988 it was Oct. 15.

The report stated that overfishing, overharvesting forests and emitting more carbon dioxide than the Earth’s ecosystems can absorb equates to using 1.7 Earths over the course of one year.

8. The Future Of Coral Reefs Isn’t Looking Great

Research in 2018 has some grim predictions for the world’s coral reefs.

The IPCC report stated that if the global surface temperature is permitted to rise by 2C, 99% of coral reefs will die.

If the global surface temperature is capped to 1.5C, the planet will still lose 70-90% of its reefs.

An assessment of sea-level rise published in Nature in June described how rising oceans will overwhelm coral reefs, and coral populations’ ability to build reefs will fail to keep up with the water increase.

The Nature report also noted that coral reefs act as natural breakwaters to protect shores from storms, and the loss of these ocean barriers could prove to be devastating for island nations.

In August, a report published in National Geographic outlined how half of the Great Barrier Reef, the world’s largest living thing, has died since 2016.

In November the chair of the Coral Specialist Group in the International Union for the Conservation of Nature, said that children born today may be “the last generation to see coral reefs in all their glory”.

Water crashing over bridge during Hurricane Harvey in Kemah Texas

Eric Overton / Getty Images

Water crashing over bridge during Hurricane Harvey in Kemah Texas

9. Global Carbon Emissions Reached A Record High This Year

Research conducted by the Global Carbon Project, launched in a series of three reports at the UN Climate summit in Poland in December, found that global carbon emissions will reach the highest level on record.

Carbon emissions in 2018 are up by 4.7% in China, 2.% in the US and 6.3% in India.

The reports stated that a growing number of cars on the roads and increasing reliance on coal are responsible for the trend.

10. The World Is Heating Up

The UN’s World Meteorological Association released a statement in December that 2018 is set to be the fourth warmest year on record.

The State of the Global Climate statement noted that 2015, 2016 and 2017 are the other warmest years recorded by the association, with 2016 taking out the top spot.

The four-year period leading up to 2018 showed a 0.9C rise in global surface temperature rise from pre-industrial temperatures.

The authors also stated that if the El Niño conditions seen in 2018 continue, which is likely by a 75 to 80% chance, 2019 is going to be warmer than 2018.