3525. Earth Tipping Points Could Destabilize Each Other in Domino Effect: Study Finds

 By Elizabeth Claire Alberts, Mongabay, June 23, 2021

• A new risk analysis has found that the tipping points of five of Earth’s subsystems — the West Antarctic Ice Sheet, the Greenland Ice Sheet, the Atlantic Meridional Overturning Circulation (AMOC), the El Niño–Southern Oscillation (ENSO) and the Amazon rainforest — could interact with each other in a destabilizing manner.
• It suggests that these changes could occur even before temperatures reach 2°C (3.6°F) above pre-industrial levels, which is the upper limit of the Paris Agreement.
• The interactions between the different tipping elements could also lower critical temperature thresholds, essentially allowing tipping cascades to occur earlier than expected, according to the research.
• Experts not involved in the study say the findings are a significant contribution to the field, but do not adequately address the timescales over which these changes could occur.

When the first tile in a line of dominoes tips forward, it affects everything in front of it. One after another, lined-up dominoes knock into each other and topple. This is essentially what could happen to ice sheets, ocean currents and even the Amazon biome if critical tipping points are crossed, according to a new risk analysis. The destabilization of one element could impact the others, creating a domino effect of drastic changes that could move the Earth into an unfamiliar state — one potentially dangerous to the future of humanity and nature as we know it.

The study, published this month in Earth System Dynamics, examines the interactions between five subsystems that are known to have vital thresholds, or tipping points, that could trigger irreversible changes. They include the West Antarctic Ice Sheet, the Greenland Ice Sheet, the Atlantic Meridional Overturning Circulation (AMOC), the El Niño–Southern Oscillation (ENSO) and the Amazon Rainforest.

Scientists believe the AMOC could reach its critical threshold when warming temperatures weaken the current enough to substantially slow it, halt it, or redirect it, which could plunge parts of the northern hemisphere into a period of record cold, even as global warming continues elsewhere. Likewise, the Antarctic ice sheet may reach its irreversible threshold when warming temperatures trigger a state of constant ice loss, which could ultimately result in a 4-meter (13-foot) rise in global sea levels over the coming centuries. In fact, it’s suggested that the West Antarctic Ice Sheet may have already passed its critical threshold, and that ice loss is unstoppable now.

Interactions between climate tipping elements and their roles in tipping cascades. Image by Wunderling et al.

These individual tipping points are largely being driven by human-caused climate change, which is considered to be one of nine planetary boundaries — scientifically identified limits on change to vital Earth systems that currently regulate and sustain life. Overshooting those boundaries could lead to new natural paradigms catastrophic for humanity. Climate change has its own threshold of 350 parts per million (ppm) of CO2, which is the amount that scientists say the atmosphere can safely hold, but this threshold was already passed in 1988. In 2021, CO2 exceeded 417 ppm, which is 50% higher than pre-industrial levels.

To conduct this new study, the research team used a conceptual modeling process to analyze the interactions between these five Earth subsystems. What they found was that more than a third of these elements showed “tipping cascades” even before temperatures reached 2° Celsius (3.6° Fahrenheit) above pre-industrial levels, which is the upper limit of the 2015 Paris climate agreement. At present, almost no nation on Earth is on target to meet its Paris carbon reduction goals.

Significantly, the study also found that the interactions between the tipping elements could lower critical temperature thresholds, essentially allowing tipping cascades to occur earlier than anticipated. Additionally, the researchers found that the Greenland Ice Sheet would function as an initiator of tipping cascades, while the AMOC would act as a transmitter that would push further changes, including dieback of the Amazon. Most of these tipping elements have been projected to have a destabilizing effect on each other, with the exception of the weakening of the AMOC, which could actually make the North Atlantic region colder and help stabilize the Greenland Ice Sheet.

Canoe in the Zacambu river, Peru. Photo by Rhett A. Butler for Mongabay.

“We found that the overall interactions tend to make [things] worse, so to say, and tend to be destabilizing,” lead author Nico Wunderling, a scientist at the Potsdam Institute for Climate Impact Research in Germany, told Mongabay.

He said that the findings suggest that we already face significant risk, but that the study does not necessarily provide a forecast.

“We have made a risk analysis,” Wunderling said. “This is not a prediction, but it’s more like, ‘OK, if we have this warming, then we might face an increasing risk of tipping cascades.’”

Tim Lenton, a professor of climate change and Earth system science at the University of Exeter, U.K., and co-author of a similar study on tipping points, says the new paper is a “useful addition to the assessment of climate tipping point interactions.”

“The important takeaway message from this study is that the cascading causal interactions between four different climate tipping elements lower the ‘safe’ temperature level at which the risk of triggering tipping points is minimized,” Lenton told Mongabay in an email. “In fact the study suggests that below 2C of global warming (above pre-industrial) — i.e. in the Paris agreement target range — there could still be a significant risk of triggering cascading climate tipping points.”

However, Lenton says the study does not unpack the timescale in which these tipping cascades would occur, focusing more on their consequences.

Iceberg off Antarctica. Image by Mongabay.

“In the case of ice sheet collapse this can take many centuries,” he said. “Hence the results should be viewed as ‘commitments’ to potentially irreversible changes and cascades that we may be making soon, but will leave as a grim legacy to future generations to feel their full impact.”

Juan Rocha, an ecologist at the Stockholm Resilience Centre, says the findings of the study affirm previous hypotheses about how “the tipping of one system can affect the likelihood of others in a self-amplifying way,” although he also notes its oversight of evaluating timescales.

“The Amazon is likely to tip way earlier than AMOC or Greenland,” Rocha told Mongabay. “Future work needs to take into account the diversity and uncertainty of the feedbacks at play for each tipping element to really understand how likely [it] is that one system can tip the other.”

Rocha says he’s pleased the authors undertook this study and hopes others continue to build on this research.

“I would like to extend an invitation to the authors and the scientific community to keep working on these important questions,” he said. “There is a lot of work to do, a lot that we do not know, and our models can only get us so far. Understanding how different systems of the Earth … are connected is fundamental to avoid the risk of domino effects, but also to empower people to act on time, identify leverage points and understand the extent of action or lack of it.”

Citations:

Cai, Y., Lenton, T. M., & Lontzek, T. S. (2016). Risk of multiple interacting tipping points should encourage rapid CO2 emission reduction. Nature Climate Change, 6(5), 520-525. doi:10.1038/nclimate2964

Wunderling, N., Donges, J. F., Kurths, J., & Winkelmann, R. (2020). Interacting tipping elements increase risk of climate domino effects under global warming. Earth System Dynamics, 12, 601-619. doi:10.5194/esd-12-601-2021

2780. Climate Tipping Points

By Casey Ivanovich and Ilissa Ocko, Environmental Defence Fund, November 8, 2017

Melting of the Greenland ice sheet in 2016

Imagine cutting down a tree. Initially, you chop and chop … but not much seems to change. Then suddenly, one stroke of the hatchet frees the trunk from its base and the once distant leaves come crashing down.

It’s an apt metaphor for one of the most alarming aspects of climate change – the existence of “tipping elements.”

These elements are components of the climate that may pass a critical threshold, or “tipping point,” after which a tiny change can completely alter the state of the system. Moving past tipping points may incite catastrophes ranging from widespread drought to overwhelming sea level rise.

Which elements’ critical thresholds should we worry about passing thanks to human-induced climate change?

You can see the answer on this graphic – and find more information below.

Image: EDF

The most immediate and most worrisome threats

• Disappearance of Arctic Summer Sea Ice – As the Arctic warms, sea ice melts and exposes dark ocean waters that reflect sunlight much less efficiently. This decreased reflectivity causes a reinforcement of Arctic warming, meaning that the transition to a sea-ice free state can occur on the rapid scale of a few decades. Some scientists have suggested that we have already passed this tipping point, predicting that Arctic summers will be ice-free before mid-century.
• Melting of the Greenland Ice Sheet – The Arctic warming feedback described above may one day render Greenland ice-free. Research predicts that the tipping point for complete melt can occur at a global temperature rise of less than two degrees Celsius – a threshold that may be surpassed by the end of this century. While the full transition to an ice-free Greenland will take at least a few hundred years, its impacts include global sea level rise of up to 20 feet.
• Disintegration of the West Antarctic Ice Sheet – The bottom of this ice sheet lies beneath sea level, allowing warming ocean waters to slowly eat away at the ice. There is evidence that this tipping point has already been surpassed – possibly as early as 2014. Like the Greenland Ice Sheet, full collapse would require multiple centuries, but it could result in sea level rise of up to 16 feet.
• Collapse of Coral Reefs – Healthy corals maintain a symbiotic relationship with the algae that provide their primary food source. As oceans warm and become more acidic, these algae are expelled from the corals in an often fatal process called coral bleaching. Research predicts that most of our remaining coral systems will collapse even before a global temperature rise of two degrees Celsius.

Tipping points in the distant future

• Disruption of Ocean Circulation Patterns – The Thermohaline Circulation is driven by heavy saltwater sinking in the North Atlantic, but this water is becoming fresher and lighter as glaciers melt in a warming climate. The change in water density may prevent sinking and result in a permanent shutdown of the circulation. Research suggests that weakening of the Thermohaline Circulation is already in progress, but that an abrupt shutdown is unlikely to occur in this century. Some models suggest that these changes may prompt a secondary tipping element in which the subpolar gyre currently located in the Labrador Sea shuts off. Such a change would dramatically increase sea level, especially on the eastern coast of the United States.
• Release of Marine Methane Hydrates – Large reservoirs of methane located on the ocean floor are stable thanks to their current high pressure-low temperature environment. Warming ocean temperatures threaten the stability of these greenhouse gas reservoirs, but the necessary heat transfer would require at least a thousand years to reach sufficient depth, and may be further delayed by developing sea level rise.
• Ocean Anoxia – If enough phosphorous is released into the oceans – from sources including fertilizers and warming-induced weathering, or the breakdown of rocks –regions of the ocean could become depleted in oxygen. However, this process could require thousands of years to develop.

Potentially disastrous elements, but with considerable uncertainty

• Dieback of the Amazon Rainforest – Deforestation, lengthening of the dry season, and increased summer temperatures each place stress on rainfall in the Amazon. Should predictions that at least half of the Amazon Rainforest convert to savannah and grasslands materialize, a considerable loss in biodiversity could result. However, the dieback of the Amazon Rainforest ultimately depends on regional land-use management, and on how El Niño will influence future precipitation patterns.
• Dieback of Boreal Forests– Increased water and heat stress could also lead to a decrease in boreal forest cover by up to half of its current size. Dieback of boreal forests would involve a gradual conversion to open woodlands or grasslands, but complex interactions between tree physiology, permafrost melt, and forest fires renders the likelihood of dieback uncertain.
• Weakening of the Marine Carbon Pump – One mechanism through which oceanic carbon sequestration takes place is the marine carbon pump, which describes organisms’ consumption of carbon dioxide through biological processes such as photosynthesis or shell building. As ocean temperatures rise, acidification progresses, and oxygen continues to be depleted, these natural systems could be threatened and render the carbon sequestration process less efficient. More research is necessary in order to quantify the timescale and magnitude of these effects.

Tipping elements complicated by competing factors

• Greening of the Sahara/Sahel – As sea surface temperatures rise in the Northern Hemisphere, rainfall is projected to increase over the Sahara and Sahel. This increased rainfall would serve to expand grassland cover in the region, but is balanced by the cooling effect of human-emitted aerosols in the atmosphere.
• Chaotic Indian Summer Monsoon – The fate of the Indian Summer Monsoon similarly depends upon a balance of greenhouse gas warming and aerosol cooling, which strengthen and weaken the monsoon, respectively. On the timescale of a year, there is potential for the monsoon to adopt dramatic active and weak phases, the latter resulting in extensive drought.

More research necessary to establish as tipping elements

• Collapse of Deep Antarctic Ocean Circulation – As in the case of the Thermohaline Circulation, freshening of surface waters in the Southern Ocean due to ice melt may slowly alter deep water convection patterns. However, the gradual warming of the deep ocean encourages this convection to continue.
• Appearance of Arctic Ozone Hole – Unique clouds that form only in extremely cold conditions currently hover over Antarctica, serving as a surface for certain chemical reactions and facilitating the existence of the ozone hole. As climate change continues to cool the stratosphere, these “ice clouds” could begin formation in the Arctic and allow the development of an Arctic ozone hole within a year.
• Aridification of Southwest North America – As global temperatures rise, consequential changes in humidity prompt the expansion of subtropical dry zones and reductions in regional runoff. Models predict that Southwest North America will be particularly affected, as moisture shifts away from the southwest and into the upper Great Plains.
• Slowdown of the Jet Stream –A narrow and fast moving air current called a jet stream flows across the mid-latitudes of the northern hemisphere. This current separates cold Arctic air from the warmer air of the south and consequentially influences weather in its formation of high and low pressure systems. A slowing of the jet stream has been observed over recent years. Should slowing intensify, weather patterns could persist over several weeks with the potential to develop into extended extreme weather conditions.
• Melting of the Himalayan Glaciers – Several warming feedbacks render the Himalayan glaciers vulnerable to dramatic melt within this century, though limitations on data availability complicate further study. Dust accumulation on the mountainous glaciers and the continual melt of snow and ice within the region both prompt a decrease in sunlight reflectivity and amplify regional warming.

Gradual, continuous changes

• More Permanent El Nino State – 90 percent of the extra heat trapped on Earth’s surface by greenhouse gases is absorbed by the oceans. Though still under debate, the most likely consequence of this oceanic heat uptake is a gradual transition to more intense and permanent El Nino/Southern Oscillation (ENSO) conditions, with implications including extensive drought throughout Southeast Asia and beyond.
• Permafrost Melting – As global temperatures rise and the high latitudes experience amplified warming, melting permafrost gradually releases carbon dioxide and methane into the atmosphere and creates a feedback for even more warming.
• Tundra Transition to Boreal Forest– Much like the conversion of the Amazon Rainforest and boreal forests to other biomes, tundra environments may transition into forests as temperatures increase. However, this process is more long-term and continuous.

With a range of critical thresholds on the horizon, each tipping element demonstrates the potential implications of allowing climate change to progress unchecked.

As tipping points loom ever closer, the urgency for emissions mitigation escalates in hopes of sustaining the Earth as we know it.

2643. Climate change: Three years to safeguard our Climate

By  Christiana Figueres, Hans Joachim Schellnhuber, Gail Whiteman, Johan Rockström, Anthony Hobley & Stefan Rahmstorf, Nature, June 28, 2017

Fort Lupton solar farm, United States. 

In the past three years, global emissions of carbon dioxide from the burning of fossil fuels have leveled after rising for decades. This is a sign that policies and investments in climate mitigation are starting to pay off. The United States, China and other nations are replacing coal with natural gas and boosting renewable energy sources. There is almost unanimous international agreement that the risks of abandoning the planet to climate change are too great to ignore.

The technology-driven transition to low-carbon energy is well under way, a trend that made the 2015 Paris climate agreement possible. But there is still a long way to go to decarbonize the world economy. The political winds are blustery. President Donald Trump has announced that the United States will withdraw from the Paris agreement when it is legally able to do so, in November 2020.

The year 2020 is crucially important for another reason, one that has more to do with physics than politics. When it comes to climate, timing is everything. According to an April report¹(prepared by Carbon Tracker in London, the Climate Action Tracker consortium, the Potsdam Institute for Climate Impact Research in Germany and Yale University in New Haven, Connecticut), should emissions continue to rise beyond 2020, or even remain level, the temperature goals set in Paris become almost unattainable. The UN Sustainable Development Goals that were agreed in 2015 would also be at grave risk.

That’s why we launched Mission 2020 — a collaborative campaign to raise ambition and action across key sectors to bend the greenhouse-gas emissions curve downwards by 2020 (www.mission2020.global).

As 20 leaders of the world’s largest economies gather on 7–8 July at the G20 summit in Hamburg, Germany, we call on them to highlight the importance of the 2020 climate turning point for greenhouse-gas emissions, and to demonstrate what they and others are doing to meet this challenge. Lowering emissions globally is a monumental task, but research tells us that it is necessary, desirable and achievable.

After roughly 1°C of global warming driven by human activity, ice sheets in Greenland and Antarctica are already losing mass at an increasing rate. Summer sea ice is disappearing in the Arctic and coral reefs are dying from heat stress — entire ecosystems are starting to collapse. The social impacts of climate change from intensified heatwaves, droughts and sea-level rise are inexorable and affect the poorest and weakest first.

The magnitude of the challenge can be grasped by computing a budget for CO2 emissions — the maximum amount of the gas that can be released before the temperature limit is breached. After subtracting past emissions, humanity is left with a ‘carbon credit’ of between 150 and 1,050 gigatonnes (Gt; one Gt is 1 × 10⁹ tonnes) of CO2 to meet the Paris target of 1.5 °C or well below 2 °C (see go.nature.com/2rytztf). The wide range reflects different ways of calculating the budgets using the most recent figures.

At the current emission rate of 41 Gt of CO2 per year, the lower limit of this range would be crossed in 4 years, and the midpoint of 600 Gt of CO2 would be passed in 15 years. If the current rate of annual emissions stays at this level, we would have to drop them almost immediately to zero once we exhaust the budget. Such a ‘jump to distress’ is in no one’s interest. A more gradual descent would allow the global economy time to adapt smoothly.

Harness momentum

The good news is that it is still possible to meet the Paris temperature goals if emissions begin to fall by 2020 (see ‘Carbon crunch’).

Greenhouse-gas emissions are already decoupling from production and consumption. For the past three years, worldwide CO2 emissions from fossil fuels have stayed flat, while the global economy and the gross domestic product (GDP) of major developed and developing nations have grown by at least 3.1% per year (see go.nature.com/2rthjje). This is only the fourth occasion in the past 40 years on which emission levels have stagnated or fallen. The previous three instances — in the early 1980s, 1992 and 2009 — were associated with global economic predicaments, but the current one is not².

Emissions from the United States fell the most: by 3% last year, while its GDP grew by 1.6%. In China, CO2 emissions fell by 1% in 2016, and its economy expanded by 6.7% (ref. 2). Although it is too early to tell whether this plateau will presage a fall, the signs are encouraging.

In 2016, two-thirds of China’s 5.4% extra demand for electricity was supplied by carbon-free energy resources, mostly hydropower and wind². In the European Union, wind and solar made up more than three-quarters of new energy capacity installed; coal demand was reduced by 10% (ref. 3). In the United States, almost two-thirds of the electricity-generating capacity installed by utility companies was based on renewables 
(see go.nature.com/2skv20g).

The International Energy Agency (IEA) has predicted that, by 2020, renewable sources could deliver 26–27% of the world’s electricity needs, compared with 23.7% of electric power at the end of 2015. But that underestimates the pace of change in energy systems.

Growth in electric vehicles alone could displace 2 million barrels of oil per day by 2025, according to a February report⁴. It suggests that, by 2050, this could reach 25 million barrels of oil per day — a stark contrast to expectations from the fossil-fuel industry that demand for oil will rise. And solar power alone could supply 29% of global electricity generation by 2050. This would remove the need for coal and leave natural gas with only a 1% market share. However, the oil firm ExxonMobil predicts that all renewables will supply just 11% of global power generation by 2040 (ref. 4).

Investors, meanwhile, are growing wary of carbon risks. BlackRock and Vanguard, the two largest fund managers, voted — along with many others — against ExxonMobil management at its annual general meeting on 31 May and instructed the company to report on the profit impact of global measures to keep climate change below 2 °C. Earlier this month, Norway’s US$960-billion sovereign-wealth fund declared that it will ask the banks in which it has invested to disclose how their lending contributes to global greenhouse-gas emissions.

Last year, the installed capacity of renewable energy set a new record of 161 gigawatts; in 2015, investment levels reached $286 billion worldwide, more than 6 times that in 2004. Over half of that investment, $156 billion, was for projects in developing and emerging economies⁵.

There is a strong headwind against the low-carbon transition in some places, which may impede progress. For example, the Financial CHOICE Act — a bill passed by the US House of Representatives on 8 June — would make it nearly impossible for investors to challenge companies on climate-risk disclosure through shareholder proposal processes, as at ExxonMobil. However, as the UN Secretary General, António Guterres, said in New York last month: “The sustainability train has left the station.” The fossil-free economy is already profitable⁶ and creating jobs (www.clean200.org). A report this year by the International Renewable Energy Agency and the IEA shows that efforts to stop climate change could boost the global economy by $19 trillion⁷. The IEA has also said that implementing the Paris agreement will unlock $13.5 trillion or more before 2050.

Recent geopolitical events, too, have galvanized activity in support of the Paris agreement. For example, the #WeAreStillIn campaign — involving more than 1,000 governors, mayors, businesses, investors and universities from across the United States — has declared that it will ensure the nation remains a leader in reducing carbon emissions.

Six milestones

To prioritize actions, we’ve identified milestones in six sectors. Developed with knowledge leaders, these were reviewed and refined in collaboration with analysts at Yale University, the Climate Action Tracker consortium, Carbon Tracker, the low-carbon coalition We Mean Business, the Partnership on Sustainable, Low Carbon Transport (SLoCaT), advisory firm SYSTEMIQ, the New Climate Economy project and Conservation International.

These goals may be idealistic at best, unrealistic at worst. However, we are in the age of exponential transformation and think that such a focus will unleash ingenuity. By 2020, here’s where the world needs to be:

Energy. Renewables make up at least 30% of the world’s electricity supply — up from 23.7% in 2015 (ref. 8). No coal-fired power plants are approved beyond 2020, and all existing ones are being retired.

Infrastructure. Cities and states have initiated action plans to fully decarbonize buildings and infrastructures by 2050, with funding of $300 billion annually. Cities are upgrading at least 3% of their building stock to zero- or near-zero emissions structures each year⁹.

Transport. Electric vehicles make up at least 15% of new car sales globally, a major increase from the almost 1% market share that battery-powered and plug-in hybrid vehicles now claim. Also required are commitments for a doubling of mass-transit utilization in cities, a 20% increase in fuel efficiencies for heavy-duty vehicles and a 20% decrease in greenhouse-gas emissions from aviation per kilometer traveled.

Land. Land-use policies are enacted that reduce forest destruction and shift to reforestation and afforestation efforts. Current net emissions from deforestation and land-use changes form about 12% of the global total. If these can be cut to zero next decade, and afforestation and reforestation can instead be used to create a carbon sink by 2030, it will help to push total net global emissions to zero, while supporting water supplies and other benefits. Sustainable agricultural practices can reduce emissions and increase CO2 sequestration in healthy, well-managed soils.

Industry. Heavy industry is developing and publishing plans for increasing efficiencies and cutting emissions, with a goal of halving emissions well before 2050. Carbon-intensive industries — such as iron and steel, cement, chemicals, and oil and gas — currently emit more than one-fifth of the world’s CO2, excluding their electricity and heat demands.

Finance. The financial sector has rethought how it deploys capital and is mobilizing at least $1 trillion a year for climate action. Most will come from the private sector. Governments, private banks and lenders such as the World Bank need to issue many more ‘green bonds’ to finance climate-mitigation efforts. This would create an annual market that, by 2020, processes more than 10 times the $81 billion of bonds issued in 2016.

Further, faster, together

If we delay, the conditions for human prosperity will be severely curtailed. There are three pressing and practical steps to avoid this.

First, use science to guide decisions and set targets. Policies and actions must be based on robust evidence. Uncensored and transparent communication of peer-reviewed science to global decision-makers is crucial. Academic journal articles are not easily read or digested by non-experts, so we need a new kind of communication in which Nature meets Harvard Business Review. Science associations should provide more media training to young scientists and hold communication boot camps on how to make climate science relevant to corporate boards and investors.

Those in power must also stand up for science. French President Emmanuel Macron’s Make Our Planet Great Again campaign is a compelling example. He has spoken out to a global audience in support of climate scientists and invited researchers to move to France to help accelerate action and deliver on the Paris agreement. To encourage others to speak, scientists should forge connections with leaders from policy, business, and civil society. The Arctic Basecamp at Davos in January, for instance, brought scientists into high-level discussions on global risk at the World Economic Forum’s annual meeting in Switzerland.

“The fossil-free economy is already profitable.”

Second, existing solutions must be scaled up rapidly. With no time to wait, all countries should adopt plans for achieving 100% renewable electricity production, while ensuring that markets can be designed to enable renewable-energy expansion.

Third, encourage optimism. Recent political events have thrown the future of our world into sharp focus. But as before Paris, we must remember that impossible is not a fact, it’s an attitude. It is crucial that success stories are shared. Demonstrating where countries and businesses have over-achieved on their targets will raise the bar for others. More-ambitious targets become easier to set.

The upcoming G20 meeting in Hamburg is the perfect moment for heads of state to integrate the six milestones into their discussions on how to ensure a resilient, prosperous, inclusive and interconnected global economy. This would pave the way for a year of raised ambition in 2018 when nations take stock of progress and revise national commitments under the Paris agreement.

The G20 is due to adopt the recommendations of the Financial Stability Board’s Task Force on Climate-related Financial Disclosures, on how the global finance system will manage the risk of climate change. It requires financial institutions to design, disclose and implement a transition strategy with a view to full decarbonization of operations, value chains and portfolios by 2050. National governments and financial regulators must enact these recommendations swiftly.

Cities and provincial governments must help to drive the ambition of national governments on climate change, particularly through smart infrastructure and transport policy. C40 Cities, a network of megacities committed to addressing climate change, has adopted a strategy called Deadline 2020 that aligns its emissions-reductions plans with the Paris agreement. Other cities now have an opportunity to follow suit, for example through the Global Covenant of Mayors for Climate and Energy.

Our co-signatory list, which includes eminent scientists, business leaders, economists, analysts, influencers and representatives of non-governmental organizations, is an example of the strength of radical collaboration across unusual partners, who all share a mission to seize this opportunity to improve people’s lives, the planet, and the global economy.

There will always be those who hide their heads in the sand and ignore the global risks of climate change. But there are many more of us committed to overcoming this inertia. Let us stay optimistic and act boldly together.

Nature 546, 593–595 (29 June 2017) doi:10.1038/546593a

References

1. Mission 2020. 2020: The Climate Turning Point (Mission 2020, 2017); available at http://go.nature.com/2takuw3
Show context

2. International Energy Agency. World Energy Outlook 2016 (International Energy Agency, 2016).
Show context

3. WindEurope. Wind in Power: 2016 European Statistics (WindEurope, 2017).
Show context

4. Carbon Tracker. Expect the Unexpected (Carbon Tracker, 2017).
Show context

5. Frankfurt School–UNEP Centre/BNEF. Global Trends in Renewable Energy Investment 2016(Frankfurt School, 2016).
Show context

6. IRENA. Renewable Energy and Jobs: Annual Review 2017 (IRENA, 2017).
Show context

7. IEA/IRENA. Perspectives for the Energy Transition (IEA/IRENA, 2017).
Show context

8. REN21. Renewables 2016: Global Status Report (REN21, 2016).
Show context

9. Climate Action Tracker. 10 Steps (Climate Action Tracker, 2016); available at http://go.nature.com/2ryh56j
Show context

Related stories and links

From nature.com

• Let Trump claim a better deal on climate
14 June 2017

• The G20 must govern the shift to low-carbon energy
07 June 2017

• Don't link carbon markets
21 March 2017

• Renewables need a grand-challenge strategy
05 October 2016

• Economics: Support low-carbon investment
04 March 2015

• Climate science: Vast costs of Arctic change
24 July 2013

From elsewhere

• Mission 2020

• G20 Germany 2017

Author information

Affiliations

. Christiana Figueres is vice-chair of the Global Covenant of Mayors for Climate and Energy, and Convener of Mission 2020.

. Hans Joachim Schellnhuber is director of the Potsdam Institute for Climate Impact Research, Germany.

. Gail Whiteman is director of the Pentland Centre for Sustainability in Business, Lancaster University, UK.

. Johan Rockström is executive director of the Stockholm Resilience Centre, Stockholm University, Sweden.

. Anthony Hobley is chief executive of Carbon Tracker, London, UK.

. Stefan Rahmstorf is head of Earth system analysis at the Potsdam Institute for Climate Impact Research, Germany.

Corresponding author

• Correspondence to: Christiana Figueres

Supplementary information

PDF files

1. Supplementary Information (74K)