Perspective on Risk - March 17, 2024 (Climate Change - It's Time To Drink)
We’ve already breached the 1.5C threshold, and global warming is accelerating rater than declining. While we need to halt the warming, we need to start preparing for the impact of a warmer world. We are behind the curve.
Here We Are
Exceeding Climate Targets
We’ve Already Blown the 1.5C Warming Goal
World's first year-long breach of key 1.5C warming limit (BBC)
For the first time, global warming has exceeded 1.5C across an entire year, according to the EU's climate service.
World leaders promised in 2015 to try to limit the long-term temperature rise to 1.5C, which is seen as crucial to help avoid the most damaging impacts.
February Is The New July
The Atlantic is currently as warm as it normally is in July. A ton of heat energy has been dumped into the oceans.
Evidence of Acceleration & Earth’s Energy Imbalance
Life on planet Earth is under siege. We are now in an uncharted territory. Unfortunately, time is up. We are entering an unfamiliar domain regarding our climate crisis, a situation no one has ever witnessed firsthand in the history of humanity.
The 2023 state of the climate report: Entering uncharted territory
Some of the most respected scientists in the climate science field and related areas of ecological and environmental research have authored a blunt assessment in a Special Edition of Bioscience magazine.
Life on planet Earth is under siege. We are now in an uncharted territory. For several decades, scientists have consistently warned of a future marked by extreme climatic conditions because of escalating global temperatures caused by ongoing human activities that release harmful greenhouse gasses into the atmosphere. Unfortunately, time is up. We are seeing the manifestation of those predictions as an alarming and unprecedented succession of climate records are broken, causing profoundly distressing scenes of suffering to unfold. We are entering an unfamiliar domain regarding our climate crisis, a situation no one has ever witnessed firsthand in the history of humanity.
… The trends reveal new all-time climate-related records and deeply concerning patterns of climate-related disasters. At the same time, we report minimal progress by humanity in combating climate change.
Rather than read this Substack, you should read this paper.
Will the Earth breach its 1.5C guardrail sooner than we thought? (Guardian)
People tend to notice when James Hansen speaks, and with good reason. Sometimes described as the godfather of climate science, Hansen came to global attention in June 1988 when he was director of the Nasa Goddard Institute for Space Studies.
Their most eye-catching conclusion, at least in terms of the global political response to the climate crisis, is that by early next year the world may have reached 1.5C warming above the long-term temperature average.
Trying to limit heating to 1.5C is a key global aspiration inscribed in the landmark Paris climate agreement, and has been widely adopted as a guardrail for avoiding worsening devastation that affects lives, livelihoods and nature.
The Data Is Telling Us Something New
I Study Climate Change. The Data Is Telling Us Something New. (NYT)
… the data we’re getting from three sources tells a worrying story about a world warming more quickly than before.
First, the rate of warming we’ve measured over the world’s land and oceans over the past 15 years has been 40 percent higher than the rate since the 1970s, with the past nine years being the nine warmest years on record.
Second, there has been acceleration over the past few decades in the total heat content of Earth’s oceans, where over 90 percent of the energy trapped by greenhouse gases in the atmosphere is accumulating.
Third, satellite measurements of Earth’s energy imbalance — the difference between energy entering the atmosphere from the sun and the amount of heat leaving — show a strong increase in the amount of heat trapped over the past two decades.
If Earth’s energy imbalance is increasing over time, it should drive an increase in the world’s rate of warming.
2023 - The Warmest Year On Record
September 2023 was the warmest September on record globally, with an average surface air temperature of 16.38°C, 0.93°C above the 1991-2020 average for September and 0.5°C above the temperature of the previous warmest September, in 2020.
September 2023 global temperature was the most anomalous warm month of any year in the ERA5 dataset (back to 1940).
The month as a whole was around 1.75°C warmer than the September average for 1850-1900, the preindustrial reference period.
The global temperature for January-September 2023 was 0.52°C higher than average, and 0.05°C higher than the equivalent period in the warmest calendar year (2016).
For January to September 2023, the global mean temperature for 2023 to date is 1.40°C higher than the preindustrial average (1850-1900).
For Europe, September 2023 was the warmest September on record, at 2.51°C higher than the 1991-2020 average, and 1.1°C higher than 2020, the previous warmest September.
The average sea surface temperature for September over 60°S–60°N reached 20.92°C, the highest on record for September and the second highest across all months, behind August 2023.
El Niño conditions continued to develop over the equatorial eastern Pacific.
Accelerated Global Warming (bye bye 1.5C)
“We would be damned fools and bad scientists if we didn’t expect an acceleration of global warming,” Hansen said. “We are beginning to suffer the effect of our Faustian bargain. That is why the rate of global warming is accelerating.”
Global heating is accelerating, warns scientist who sounded climate alarm in the 80s (Guardian)
Global heating is accelerating faster than is currently understood and will result in a key temperature threshold being breached as soon as this decade, according to research led by James Hansen, the US scientist who first alerted the world to the greenhouse effect.
This alarming speed-up of global heating, which would mean the world breaches the internationally agreed 1.5C threshold set out in the Paris climate agreement far sooner than expected, risks a world “less tolerable to humanity, with greater climate extremes”, according to the study led by Hansen
Global temperature in the current El Nino, to date, implies a strong acceleration of global warming
El Nino Fizzles. Planet Earth Sizzles. Why? (Hansen, Sato, Ruedy, & Simons)
Global temperature in the current El Nino, to date, implies a strong acceleration of global warming for which the most likely explanation is a decrease of human-made aerosols as a result of reductions in China and from ship emissions. The current El Nino will probably be weaker than the 1997-98 and 2015-16 El Ninos, making current warming even more significant. The current near-maximum solar irradiance adds a small amount to the major “forcing” mechanisms (GHGs, aerosols, and El Nino), but with no long-term effect. More important, the long dormant Southern Hemisphere polar amplification is probably coming into play.
Tipping Points & Impact
Harmful tipping points in the natural world pose some of the gravest threats faced by humanity. Their triggering will severely damage our planet’s life-support systems and threaten the stability of our societies.
The specific “tipping points” they discuss are:
Ice Sheets: The Greenland and West Antarctic ice sheets are already at risk of crossing tipping points at current levels of global warming. Other parts of the Antarctic ice sheet may tip at higher warming levels.
Coral Reefs: Warm-water coral reefs are likely tipping already, with significant loss of biodiversity and ecosystem services.
Ocean Circulation: The Atlantic Meridional Overturning Circulation (AMOC) and North Atlantic Subpolar Gyre are identified as being at risk, which could have major implications for climate, sea-level rise, and marine ecosystems.
Permafrost: Thawing permafrost regions are a tipping element, with implications for carbon release and global warming.
Forests and Biodiversity: Amazon rainforest dieback, boreal forest shifts, and the loss of mangroves and seagrass meadows are identified as potential tipping points, each with massive implications for carbon storage, biodiversity, and ecosystem services.
Rapid disintegration and weakening of ice shelves in North Greenland
The glaciers of North Greenland are hosting enough ice to raise sea level by 2.1 m, and have long considered to be stable. This part of Greenland is buttressed by the last remaining ice shelves of the ice sheet. Here, we show that since 1978, ice shelves in North Greenland have lost more than 35% of their total volume, three of them collapsing completely
The Great Barrier Reef’s latest bout of bleaching is the fifth in eight summers – the corals now have almost no reprieve (The Conversation)
For the fifth time in just the past eight summers – 2016, 2017, 2020, 2022 and now 2024 - huge swathes of the Great Barrier Reef are experiencing extreme heat stress that has triggered yet another episode of mass coral bleaching.
Physics-based early warning signal shows that AMOC is on tipping course (Science)
@IPCC_CH report attributes 10% probability to the collapse of the current system before 2100.
Amazon rainforest at the threshold: loss of forest worsens climate change (Potsdam Institute For Climate Impact Research)
The Southeastern Amazon has already shifted from a carbon sink to a source
The study finds that by the year 2050, 10-47 percent of the Amazonian forests will be threatened by increasing disturbances, risking to cross a tipping point.
If … temperature reaches 1.5°C..plus degradation, fires and deforestation, the south, center and east of the Amazon will pass the tipping point..we will lose between 50% and 70% of the forest
Rapid intensification (RI) of hurricanes is notoriously difficult to predict and can contribute to severe destruction and loss of life. While past studies examined the frequency of RI occurrence, changes in RI magnitude were not considered. Here we explore changes in RI magnitude over the 30‐year satellite period of 1986–2015. In the central and eastern tropical Atlantic, which includes much of the main development region, the 95th percentile of 24‐hr intensity changes increased at 3.8 knots per decade. In the western tropical Atlantic, encompassing the Caribbean Sea and the Gulf of Mexico, trends are insignificant. Our analysis reveals that warming of the upper ocean coinciding with the positive phase of Atlantic Multidecadal Oscillation, and associated changes in the large‐scale environment, has predominantly favored RI magnitude increases in the central and eastern tropical Atlantic. These results have substantial implications for the eastern Caribbean Islands, some of which were devastated during the 2017 hurricane season.
Aviation turbulence strengthened as the world warmed
At a typical point over the North Atlantic – one of the world’s busiest flight routes – the total annual duration of severe turbulence increased by 55% from 17.7 hours in 1979 to 27.4 hours in 2020, the research found. Moderate turbulence increased by 37% from 70.0 to 96.1 hours, and light turbulence increased by 17% from 466.5 to 546.8 hours.
As heatwaves become more frequent, intense, and longer-lasting due to climate change, the question of breaching thermal limits becomes pressing. A wet-bulb temperature (Tw) of 35 °C has been proposed as a theoretical upper limit on human abilities to biologically thermoregulate. But, recent—empirical—research using human subjects found a significantly lower maximum Tw at which thermoregulation is possible even with minimal metabolic activity. Projecting future exposure to this empirical critical environmental limit has not been done. Here, using this more accurate threshold and the latest coupled climate model results, we quantify exposure to dangerous, potentially lethal heat for future climates at various global warming levels. We find that humanity is more vulnerable to moist heat stress than previously proposed because of these lower thermal limits. Still, limiting warming to under 2 °C nearly eliminates exposure and risk of widespread uncompensable moist heatwaves as a sharp rise in exposure occurs at 3 °C of warming. Parts of the Middle East and the Indus River Valley experience brief exceedances with only 1.5 °C warming. More widespread, but brief, dangerous heat stress occurs in a +2 °C climate, including in eastern China and sub-Saharan Africa, while the US Midwest emerges as a moist heat stress hotspot in a +3 °C climate. In the future, moist heat extremes will lie outside the bounds of past human experience and beyond current heat mitigation strategies for billions of people. While some physiological adaptation from the thresholds described here is possible, additional behavioral, cultural, and technical adaptation will be required to maintain healthy lifestyles.
Climate Science Update
Earth’s Energy Imbalance
Accelerated Concentrations of Greenhouse Gases
Global warming in the pipeline
Hansen, et. al., the OG of climate change, have written a new paper
Equilibrium global warming for today’s GHG amount is 10°C, which is reduced to 8°C by today’s human-made aerosols. Equilibrium warming is not ‘committed’ warming; rapid phaseout of GHG emissions would prevent most equilibrium warming from occurring. However, decline of aerosol emissions since 2010 should increase the 1970–2010 global warming rate of 0.18°C per decade to a post-2010 rate of at least 0.27°C per decade. Thus, under the present geopolitical approach to GHG emissions, global warming will exceed 1.5°C in the 2020s and 2°C before 2050.
Michael Mann, former director of NASA Goddard Institute and another prominent voice on global warming, has written something of a rebuttal” Comments on New Article by James Hansen.
Jim and his co-authors are very much out of the mainstream with their newly published paper in the journal Oxford Open Climate Change. That’s fine, healthy skepticism is a valuable thing in science. But the standard is high when you’re challenging the prevailing scientific understanding, and I don’t think they’ve met that standard, by a longshot, for the following reasons:
Our best estimates today are that surface warming stops when carbon emissions stop, i.e. that there is no additional surface warming in the pipeline when emissions reach zero. The notion that there are decades of committed surface warming after emissions reach zero is based on outdated simulations that did not take into account the interactive role of the ocean carbon cycle.
The claim that the energy imbalance is increasing is not supported by ocean heat content data.
There is, furthermore, no statistical support for the claim that surface warming is currently accelerating. … The truth, once again, is bad enough.
There is no evidence that the models are under-predicting human-caused warming.
There is no evidence that changes in ship-based aerosols have played any substantial role at all in recent warming trends.
Implications & Responses
Coevolution of Extreme Sea Levels and Sea-Level Rise Under Global Warming (AGU)
The gradual increase of global mean sea level (MSL), known as sea-level rise (SLR), is one of the biggest climate change-related concerns of the 21st century. SLR poses a threat to seaside communities and can lead to an increase in the frequency and severity of coastal flooding. Thus, evaluating the future expected number of extreme sea-level events and their magnitudes is critical for sustainable coastal flood risk management. In this work, we show significant increasing trends in extreme sea levels at a “pseudo-global” scale, cross-examined by different trend detection methods. Hence, we model coming coastal flood hazard with the assumption that MSL will continue to rise in the future. This is the first global-scale study that utilizes a physical covariate, that is, MSL for explicit statistical modeling of the evolving coastal flood hazard. By using revised SLR projections that account for uncertainty, we show a substantial increase in coastal flood hazard by end of the century, either under a moderate or a high CO2 concentration pathway.
The insurance world is flirting with its climate doom loop (FT)
A 2C world might be insurable, a 4C world certainly would not be.
For climate scientist Michael Mann, the ability to cover the effects of climate change is being tested sooner than expected. “Climate models have likely underpredicted the impact of climate change on the sorts of persistent weather extremes behind the devastating wildfires, floods and heatwaves we’ve seen in recent summers,” he says.
Measures that obscure the appropriate pricing of climate risk also contribute to a vicious circle. California’s agreement, which allows prices to rise as insurers incorporate forward-looking modelling and reinsurance costs into rate setting, is progress. But the political instinct to use publicly funded alternatives to plug gaps — whether in US federal flood insurance, Florida’s state safety net or the UK’s Flood Re — tends to depress prices that should send a red alert to those building in or moving to high-risk areas. The continued growth of high-risk, high-value areas is another factor behind mounting losses.
We hypothesize that ice mass loss from the most vulnerable ice, sufficient to raise sea level several meters, is better approximated as exponential than by a more linear response.
The modeling, paleoclimate evidence, and ongoing observations together imply that 2 °C global warming above the preindustrial level could be dangerous.