By Jeff Obbard, PhD. 8 April 2024.The ‘State of the Global Climate’ report released by the UN World Meteorological Organization (WMO) takes the annual pulse of our planet’s climate system. In its latest report, of March 2024, the WMO issued a ‘Red Alert’ as every single climate change indicator had set a new record in 2023, notably:

Record-breaking warmth: In 2023, the global average near-surface temperature reached 1.45°Celsius above the pre-industrial baseline, making it the warmest year on record. Additionally, the entire decade from 2014 to 2023 was the warmest ten-year period ever recorded.

Greenhouse gas levels: Concentrations of atmospheric greenhouse gases (GHGs): carbon dioxide, methane, and nitrous oxide, continued to rise, trapping ever more heat in the Earth’s climate system.

Ocean heat and sea level rise: Ocean heat content and sea level reached record highs. The oceans act as a crucial heat reservoir, absorbing excess over 90% of the excess energy from the atmosphere. Sea surface temperatures reached an all-time high across the world’s oceans, threatening biodiverse marine ecosystems, such as coral reefs.

Antarctic sea Ice and glacier changes: Antarctic Sea ice hit record observed lows, and glaciers around the world suffered record losses, affecting freshwater availability and contributing to rising seas

Extreme Weather Events: Heatwaves, floods, droughts, wildfires, and intensifying tropical cyclones caused widespread damage and economic losses in 2023. These extreme events disrupted everyday life for millions of people and resulted in record wildfires in Canada and Europe.

So severe was the warming in 2023 that climate scientists are still struggling to explain why records were not just broken, but, in many cases, smashed, with one eminent scientist describing the dramatic changes “Absolutely gobsmackingly bananas!

It is now over 30 years, since the world pledged at the 1992 United Nations Framework Convention on Climate Change (UNFCCC) in Brazil to prevent “dangerous man-made interference with the climate system.” The world came together again in 2015 under the Paris Agreement to strengthen the response to the threat of global climate change and pledged to limit the global temperature rise in the 21st century to no more 2°C above pre-industrial levels, and pursue e?orts to curb warming to an increase of no more than 1.5°C.

Prompted by the legally binding interna?onal treaty in Paris, the UN Intergovernmental Panel on Climate Change (IPCC) published a report in 2018 on the impacts of global warming at 1.5°C. The report emphasized the need to limit global warming to below the 1.5^oC guardrail to avoid what the IPCC referred to as abrupt and irreversible changes to the global climate system.

Since 1992 global emissions of planet-hea?ng GHG, derived mainly from our combus?on of fossil fuels, in the form of coal, oil and gas, have risen by 60%, and every year since the Paris Agreement has been a record-breaking warm year. So, it was hardly surprising to climate scientists when the European Copernicus Climate Service announced in February that, for the first time in the observational record the world had exceeded 1.5^oC of warming for an entire 12-month period. There were even a few days in November 2023 that surpassed the upper 2^oC limit of the Paris Agreement.

To get our heads around where we are today with global warming and where we are headed, then it is vital to understand the operating system of the global environment upon which we all fundamentally depend. Professor Johan Rockström, a prominent climate scientist & Director of the Potsdam Institute for Climate Impact Research in Germany, has been a key advocate for humanity to gain a deeper understanding of Earth’s ‘planetary boundaries’ which define the limits in which we must run the global economy if civilization & nature are to thrive for generations to come.

Prof. Rockström and colleagues have defined a total of nine planetary boundaries that are vital for maintaining the stability of the climate system and our key global ecosystems. Crossing the boundaries increases the risk of large-scale, irreversible environmental change. In September 2023, a team of scientists, including Rockström, quantified all nine planetary boundaries, and what they found was profoundly shocking: six out of these nine boundaries have already been transgressed. Here is a summary of each of the nine planetary boundaries and their current status:

1.     Climate Change:

• Threshold: Staying below a global average temperature increase of 1.5°C above pre-industrial levels.
  • Status: Unfortunately, we’ve already surpassed this boundary. Urgent climate action is essential to prevent further warming.

2.     Stratospheric Ozone Depletion:

• Threshold: Avoiding significant depletion of the ozone layer.
  • Status: Currently, we are within safe limits due to international efforts to ban harmful substances like chlorofluorocarbons (CFCs).

3.      Land System Change:

• Threshold: Preventing excessive deforestation and habitat loss.

• Status: Unfortunately, this boundary has been crossed due to widespread land use changes, impacting biodiversity.

4.      Freshwater Consumption:

• Threshold: Maintaining sustainable freshwater use.
  • Status: humanity has exceeded this boundary. Proper management is crucial, especially considering that only 2.5% of Earth’s water is freshwater.

5.      Nitrogen and Phosphorus Flows:

• Threshold: Avoiding disruptions in essential nutrient cycles.
  • Status: This boundary has been crossed, adversely affecting ecosystems and water quality.

6.      Biodiversity:

• Threshold: Preventing significant loss of species and ecosystems.
  • Status: This boundary has been crossed. Urgent conservation efforts are necessary to protect planetary biodiversity.

7.      Atmospheric Aerosol Loading:

• Threshold: Limiting aerosol pollution.
  • Status: Despite rising pressures, we have not yet transgressed this boundary.

8.      Chemical Pollution:

• Threshold: Avoiding harmful pollutants and novel entities.
  • Status: Unfortunately, humanity has exceeded this boundary related to environmental pollutants and plastics.

9.      Ocean Acidification:

• Threshold: Preventing excessive acidification of oceans.
  • Status: This boundary remains a critical concern, adversely impacting marine ecosystems.

Urgent action is needed to prevent further warming of the climate and stay within the limits set by the Paris Agreement. However, focusing solely on climate change is insufficient; understanding the interplay of inter-connected boundaries, including biodiversity loss, is crucial if we are to avoid tipping points in the climate system. Efforts to limit warming and stay restore the planetary boundaries and a ‘safe operating space’ for humanity are essential for a sustainable and resilient future. Already the United Nations Environment Programme (UNEP) is warning us that, given our current GHG emissions trajectory, there is no credible pathway remaining to limit global warming to 1.5°C. Current data indicates that the world is on track for a temperature rise of about 2.7°C by the end of this century, provided that all pledges made under the Paris Agreement are met. In reality, the world is way-off track in meeting these targets, and fossil fuel consumption continues to increase meaning that 3-4^oC of warming by 2100 is a distinct possibility.

To add to the challenge, climate scientists are warning us that the rate that the planet heating up is also speeding up! Professor James Hansen, perhaps the world’s best known climate scientist and former director of the US National Aeronautic & Space Administration (NASA), has recently reported that global warming is accelerating faster than most of the global climate models (GCMs) that are used by the IPCC to project global warming are projecting.

The GCMs may be underestimating the risk of climate change as the models do not fully account for the sensitivity of the climate system to increased GHG concentrations, or the role of atmospheric aerosols which serve to cool the planet and offset some of the warming from heat-trapping GHGs.

Prof. Hansen has emphasized the importance of understanding the most fundamental metric of our climate system: the Earth’s energy imbalance (EEI). EEI is the driving force behind future levels of global warming, and represents the difference between the amount of energy the Earth receives from the Sun and the energy that the planet reflects and radiates back to space. If there is more energy coming into the Earth’s climate system than going out to space then the planet inevitably warms-up. Here are the key points from Prof. Hansen’s recent work:

1.     EEI and Climate Forcings:

• EEI is the net energy imbalance that determines whether Earth is gaining or losing heat.
  • Climate forcings, such as greenhouse gases (GHGs) and aerosols, alter EEI.
  • GHGs trap heat, causing a positive energy imbalance (warming), while aerosols reflect sunlight (cooling).

2.     Human-Made Climate Forcings:

• GHGs (such as carbon dioxide) reduce heat radiation to space, leading to warming.
  • Aerosols reflect sunlight back to space, contributing to cooling.

3.     Paris Agreement and Urgency:

• The goal of the Paris Agreement is to keep global warming well below 2°C above pre- industrial levels. However, Hansen argues that the goal is already dead if we rely solely on emission reductions and unproven CO2 removal methods.
  • Delayed climate response poses a grave threat, especially for young people.

Worryingly, based upon observations by NASA and the US National Oceanographic & Atmospheric Administration (NOAA) show that the EEI has doubled in the last 15-20 years, meaning ever more energy coming into the Earth’s climate system than going out to space. Hansen and his team have pinned this dramatic increase to increased GHG emissions, and to global reductions in the emission of planet-cooling aerosols. Satellite and ocean measurements show that over 90% of excess heat is going into the world’s oceans.

The increase in global ocean heat content, as a result, has been estimated to be the energy equivalent of detonating about 9000,000 Hiroshima-sized nuclear bombs per day. This likely explains the ongoing record sea surface temperatures being recorded across the world’s oceans. According to Hansen, the growing EEI has led to an acceleration in the rate of global warming from 0.18^oC per decade to 0.3^oC per decade. On this basis, the 1.5C limit of the Paris Agreement looks set to be finally breached in the longer term by the late 2020’s, and the 2^oC limit by the mid-to-late 2030s. In other words, the Earth’s climate system has entered unchartered territory.

Prof Hansen’s research underscores the urgency of understanding ongoing climate change and the mechanisms responsible for it. While avoiding near-term climate impacts is challenging, most scientists agree that we can still avoid catastrophic impacts if international pledges & global policies to limit warming are strengthened and rapidly implemented.

Indeed, the UN, under the IPCC, has called for a near 50% reduction in GHG emissions by 2030 with emissions needing to reach net-zero by mid-century. Both the UN and the International Energy Agency have also stated clearly that there is no room left for further fossil fuel infrastructure

development, where the existing infrastructure alone is more than enough to takes us above the 1.5^oC of warming. The transition to a clean, low-carbon, renewable energy must, in the words of the IPCC be “rapid and immediate” to give any reasonable chance of keeping the world warming dangerously past 1.5^oC. In other words, it is ‘now or never’ if we are to avoid catastrophic climate change.

Despite the recent evidence of our climate system entering unchartered territory and the rate of warming accelerating, it is still worth remembering that 1.5^oC of warming is not a threshold of ‘no return’. It is not as though as soon as we pass that number, Antarctic ice sheets will suddenly collapse or ocean circulation will grind to a halt. But one thing is certain: for every tenth of a degree of warming above the 1.5^oC guardrail the risk of crossing irreversible climate tipping points becomes ever are more likely. At each tenth of a degree of warming, the infrastructure and systems that the world has built — electric grids, homes, livelihoods — will become more strained. Our modern world simply was not designed for temperatures this high, and every tonne of GHG emissions avoided counts.

Climate change is not only a dire threat to planetary health but, by de-facto, human health. The latest IPCC climate assessment report tells us that we not only have a narrowing window of opportunity to secure a sustainable future, but also a liveable one. If Hansen is right about climate change acceleration, then the stakes could not be higher. So, hold onto your hats & buckle up – the transition to our low-carbon future could turn out to be a very bumpy ride indeed!

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Professor Jeff Obbard has his own Climate Change Consultancy: Science, Adaptation, Mitigation, Risk Assessment. He is Affiliate Scientist with the Centre for Climate Change Research Singapore and Visiting Professor, School of Water, Energy & Environment, Cranfield University, UK. For a landmark project, he has been Climate Change Advisor to NYAA Council. Project completed in 2021 (renewed in 2022) on the reduction of carbon emissions and business operational costs for Small and Medium sized Enterprises in Singapore. Project sponsored by HSBC Singapore, in association with the Institute of Technical Education. See the book about this: “Shaping a sustainable future: in support of the Singapore

Green Plan 2030”. (For a copy go to: www.nyaa.org). Look out for Jeff’s next book “Hothouse Asia”.