Carbon dioxide growing rapidly

The image below shows NOAA monthly mean concentration of carbon dioxide (CO₂) recorded at Mauna Loa, Hawaii, from 2020 through July 2024. The inset shows that CO₂ was 425.55 parts per million (ppm) in July 2024, an increase of 3.72 ppm from July 2023, when CO₂ was 421.83 ppm. This 3.72 ppm growth is higher than the 3.36 ppm annual growth in 2023, the highest annual growth on record. 

The image below shows the same data, with a trend added based on August 2009 through July 2024 data.

The above trend points at 430 ppm CO₂ getting crossed in February 2025, which would constitute a jump of 10 ppm in two years time (from 420 ppm in February 2023 to 430 ppm in February 2025). Despite numerous warnings and despite politicians' pledges to act decisively, the concentration of CO₂ in the atmosphere is growing rapidly.

If this trend continues, 1200 ppm CO₂ could be crossed in early 2035, as illustrated by the image below.  

In other words, the clouds tipping point could get crossed in early 2035 due to rising CO₂ alone. 

There has been some debate as to when the clouds tipping point would get crossed. The above image points at carbon dioxide in the atmosphere crossing 1200 ppm in 2035. Someone argued that, when calculating the carbon dioxide equivalent (CO₂e) for different gases, counting should start from the year 1750, implying that the clouds tipping point would not be at 1200 ppm CO₂ but would instead be reached by an increase of 1200 ppm above the CO₂ concentration in the year 1750, which was 278 ppm. Adding 1200 ppm to 278 ppm makes 1478 ppm. The image below illustrates that, if the trend would continue, this higher value of 1478 ppm could be crossed in 2036. 

[ from earlier post ]

Rising emissions could originate from many sources, the more so as more sinks turn into sources.

[ from earlier post ]

The clouds tipping point is at 1200 ppm CO₂e (carbon dioxide equivalent), so it could be crossed even earlier when also taking into account more methane, nitrous oxide, etc. The above image, from an earlier post, warns that a trend (added to NOAA globally averaged marine surface monthly mean methane data from April 2018 to November 2022) points at 6000 ppb methane in 2027. The image further warns that this could cause the clouds tipping point to get crossed due to methane alone, and illustrates this by comparing 6000 ppb methane with 1200 ppm CO₂e while using a Global Warming Potential (GWP) of 200.

Not all equivalents are equal

There are several ways to measure the impact of methane. In the above image, methane parts are taken as equivalent to carbon dioxide parts, while using a GWP for methane of 200. Not all equivalents are equal, so here's another way to compare CO₂'s and methane's impact. 

The image on the right, by Eric Fisk, shows contributions to 2010–2019 warming relative to 1850–1900 in °C. The whiskers show likely ranges, indicating that methane's impact may rival, if not exceed carbon dioxide's impact, and there are reasons why this may be the case.

[ from FAQ ]

Methane concentrations have risen strongly since 2010-2019.

Methane's immediate GWP may exceed 200, much higher than the values that are often used when applying horizons of 20 years or 100 years. 

Methane's lifetime extends as more methane is released, due to hydroxyl depletion, as illustrated by the graph on the right, based on data by Isaksen et al. (2011).

Indirect effects include more stratospheric water vapor and tropospheric ozone. Carbon dioxide is produced when methane is broken down. Methane's lifetime also extends as more water vapor enters the atmosphere, as temperatures rise.

The study by Isaksen et al. calculates that a scenario of 7 times current methane (image below, medium light colors) over 50 years would correspond with a radiative forcing of 3.6 W m⁻². 

[ from FAQ ]

At the time of the study, little was known about the clouds tipping point, let alone that it could be crossed due to methane alone at concentrations much lower than 7 times the methane in 2011. Even when using a lower value for methane's impact, there is a growing potential for the amount of methane in the atmosphere to increase dramatically, as a result of methane releases from permafrost, as temperatures keep rising, which would strongly contribute to cause the Clouds Tipping Point to get crossed. This increases the urgency to take climate action. The images below illustrate the danger. 

The above image, adapted from Copernicus, shows a methane forecast for August 22, 2024 03 UTC (run 00 UTC). Note that the scale goes up to 10 ppm or 10,000 parts per billion (ppb). 

The above image shows that high methane concentrations (around 2400 ppb) were recently recorded at the observatory in Utqiagvik (Barrow), Alaska.

As discussed in an earlier post, peak daily average methane is approaching 2000 ppb at Mauna Loa, Hawaii. Local peaks can be much higher, as illustrated by the image on the right that shows that a methane peak of 2739 ppb was recorded at 399 mb by the NOAA 20 satellite on August 22, 2024 AM. 

Methane levels are particularly high at latitudes higher than 60°N, where they can often exceed 2000 ppb, even at relatively low altitudes. 

The next image on the right shows methane as recorded by the NOAA 20 satellite on August 13, 2024 AM at 1000 mb, which corresponds with the lowest altitude available. 

The next image on the right shows methane on August 23, 2024 AM at 840 mb, where the NOAA 20 satellite recorded levels as high as 2418 ppb. 

When using a GWP of 200 for methane, a concentration of 2000 ppb may correspond with 400 ppm CO₂e, as discussed above. Together with a daily peak CO₂ concentration of 430 ppm, this would add up to a joint CO₂e peak of 830 ppm, i.e. only 370 ppm away from the clouds tipping point at 1200 ppm CO₂e. This 370 ppm CO₂e could be added almost instantly by a burst of seafloor methane less than the size of the methane that is currently in the atmosphere (about 5 Gt). 

There is plenty of potential for such an abrupt release, given the rising ocean heat and the vast amounts of carbon and methane contained in vulnerable sediments at the seafloor of the Arctic Ocean, as discussed above and in earlier posts such as this one, and at the threat page.

[ image from the Extinction page ]

There are further emissions and developments such as tipping points and feedbacks that should be taken into account. The above image, from an earlier post, illustrates the mechanism how multiple feedbacks can accelerate the temperature rise of the atmosphere.

Several feedbacks can also constitute tipping points. Decline of Arctic sea ice comes with loss of albedo and loss of the Latent Heat Buffer, and the joint loss can abruptly and dramatically increase temperatures in the Arctic Ocean.

Further increase of heat in the Arctic Ocean can in turn cause the Seafloor Methane Tipping Point to get crossed, resulting in destabilization of methane hydrates contained in sediments at the seafloor of the Arctic Ocean, as discussed in many earlier posts such as this one.

Self-amplifying feedbacks and crossing of tipping points, as well as further developments (such a as loss of the aerosol masking effect and sunspots reaching a peak) could all contribute to cause a temperature rise from pre-industrial of over 10°C, in the process causing the clouds tipping point to get crossed that can push up the temperature rise by a further 8°C.

Altogether, the temperature rise may exceed 18°C from pre-industrial by 2026, as illustrated by the image on the right.

Climate Emergency Declaration

The situation is dire and the precautionary principle calls for rapid, comprehensive and effective action to reduce the damage and to improve the situation, as described in this 2022 post, where needed in combination with a Climate Emergency Declaration, as discussed at this group.

Links

• NOAA - Global Monitoring Laboratory - Carbon Cycle Gases, trends in CO2
https://gml.noaa.gov/ccgg/trends

• NOAA - Global Monitoring Laboratory - Carbon Cycle Gases, Mauna Loa, Hawaii, U.S.
https://gml.noaa.gov/dv/iadv/graph.php?code=MLO&program=ccgg&type=ts

• Copernicus - methane forecasts
https://atmosphere.copernicus.eu/charts/packages/cams/products/methane-forecasts

• The Clouds Feedback and the Clouds Tipping Point
https://arctic-news.blogspot.com/p/clouds-feedback.html

• Albedo
https://arctic-news.blogspot.com/p/albedo.html

• Feedbacks in the Arctic
https://arctic-news.blogspot.com/p/feedbacks.html

• Jet Stream
https://arctic-news.blogspot.com/p/jet-stream.html

• Latent Heat
https://arctic-news.blogspot.com/p/latent-heat.html

• Cold freshwater lid on North Atlantic
https://arctic-news.blogspot.com/p/cold-freshwater-lid-on-north-atlantic.html

• Sunspots
https://arctic-news.blogspot.com/p/sunspots.html

• Pre-industrial
https://arctic-news.blogspot.com/p/pre-industrial.html

• Extinction
https://arctic-news.blogspot.com/p/extinction.html

• Transforming Society
https://arctic-news.blogspot.com/2022/10/transforming-society.html

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

• Climate Emergency Declaration
https://arctic-news.blogspot.com/p/climate-emergency-declaration.html

Paris Agreement thresholds crossed

High temperatures persist

The image below, created with NASA data while using a 1903-1924 custom base, illustrates that the temperature anomaly through July 2024 has been more than 1.5°C above this base for each of the past consecutive 13 months, and even more when compared to a pre-industrial base. The red line shows the trend (one-year Lowess Smoothing) associated with the rapid recent rise.

On August 19, 2024, the daily global air temperature was 16.9°C (62.42°F), an anomaly of +0.8°C (+1.44°F) versus 1991-2020, the highest temperature and anomaly on record for this day of the year, as illustrated by the image below, adapted from Copernicus. 

Copernicus has meanwhile upgraded the anomaly versus 1991-2020 to 0.81°C (1.458°F) for August 19, 2024. Climate Reanalyzer recorded an anomaly versus 1991-2020 of 0.82°C (1.476°F) for August 19, 2024, as illustrated by the image below. 

Temperatures have been high for 14 consecutive months, i.e. about 0.8°C  (± 0.3°C) above the 1991-2020 average and much more when compared to a pre-industrial base, with no sign of a return to earlier temperatures. On August 31, 2024, the temperature was 0.78°C above 1991-2020, the highest anomaly on record for that day of the year. 

ENSO-neutral conditions are currently present and a transition to La Niña is expected by September-November 2024, as illustrated by the image below, adapted from NOAA. The La Niña may be short-lived and a transition to the next El Niño may occur in the course of 2025. 

The image below, adapted from NOAA, illustrates that El Niño conditions were present from June 2023 through April 2024, and that ENSO-neutral started in May 2024. 

The danger is that we could move into a new El Niño in 2025, while temperatures remain high due to feedbacks and while sunspots move toward the peak of this cycle, expected to occur in July 2025. This - in combination with further events and variables - could constitute a cataclysmic alignment that could result in runaway temperature rise by 2026, as an earlier post concluded and as illustrated by the image below.

In a cataclysmic alignment, the next El Niño threatens to develop while sunspots are higher than expected and peak in July 2025.

As emissions keep rising, feedbacks threaten to grow in strength and strike with ever greater ferocity, further accelerating the temperature rise while extreme weather disasters hit the world more frequently over larger areas, with greater intensity and for longer periods.

Heatwaves, fires, famine, drought, floods, crop loss, loss of habitable land and corrupt politicians threaten violent conflicts to erupt around the world, industrial activity to grind to a halt and the temperature to rise above 3°C from pre-industrial, driving humans into extinction by 2026.

IPCC keeps downplaying the danger

Note that neither the 1903-1924 base, nor the 1991-2020 base, nor the 1901-2000 base in above images is pre-industrial. The IPCC keeps downplaying the danger, e.g. by claiming that we're still well below the 1.5°C threshold, but when using a genuinely pre-industrial base, the temperature anomaly has for the past thirteen months also been above the 2°C threshold that politicians at the 2015 Paris Agreement pledged wouldn't be crossed.

[ from earlier post ]

The above image, from an earlier post, shows that the February 2024 temperature was 1.76°C above 1885-1915, potentially 2.75°C above pre-industrial (bright yellow inset right). The red line (a 6 months Lowess smoothing trend) highlights the steep rise that had already taken place by then.

[ image from a 2014 post ]

Additionally, the IPCC refers to a "carbon budget" as if there was an amount of carbon to be divided among polluters and to be consumed for decades to come.

The image on the right illustrates the fallacy of offsets, net-zero and a "balance" between sources and sinks.

Instead, comprehensive and effective action is needed on multiple lines of action, simultaneously yet separately.

Indeed, action is needed to reduce concentrations of carbon both in oceans and in the atmosphere, while on land, the soil carbon content needs to increase, which can be achieved by methods such as pyrolysis of biowaste and adding the resulting biochar to the soil, which will reduce emissions, reduce fire hazards, sequester carbon, support the presence of moisture & nutrients in the soil and thus support the health & growth of vegetation, as discussed at the Climate Plan group and the biochar group.

The IPCC has not only failed to warn about the size of the temperature rise from pre-industrial, the IPCC has also failed to warn about developments contributing to such a rise and failed to point at the best ways to combat the rise. 

Higher temperatures come with feedbacks, as illustrated by the image below, from an earlier post.

As illustrated by the image below, adapted from Climate Reanalyzer, the July 2024 temperature anomaly was huge over and around much of Antarctica.

As illustrated by the image below, also adapted from Climate Reanalyzer, Antarctic temperatures were still increasing in early August, 2024. 

The IPCC failed to warn about Antarctic snow and ice cover decline, and - importantly - the amplifying impact of Antarctic sea ice decline on the global temperature rise. This was addressed in an earlier post as follows: 
Sea ice loss results in less sunlight getting reflected back into space and instead getting absorbed by the ocean and the impact of Antarctic sea ice loss is even stronger than Arctic sea ice loss, as Antarctic sea ice is located closer to the Equator, as pointed out by Paul Beckwith in a video in an earlier post. A warmer Southern Ocean also comes with fewer bright clouds, further reducing albedo, as discussed here and here. For decades, there still were many lower clouds over the Southern Ocean, reflecting much sunlight back into space, but these lower clouds have been decreasing over time, further speeding up the amount of sunlight getting absorbed by the water of the Southern Ocean, and this 'pattern effect' could make a huge difference globally, as this study points out. Emissivity is a further factor; open oceans are less efficient than sea ice when it comes to emitting in the far-infrared region of the spectrum (feedback #23 on the feedbacks page).

Sea surface temperatures in the Northern Hemisphere

After an astonishing rise in 2023, sea surface temperature anomalies fell for six months in the Northern Hemisphere and then rose again for four months, threatening to cause dramatic sea ice loss over the next few months and destabilize sediments at the seafloor, resulting in huge amounts of methane erupting and abruptly entering the atmosphere.

[ image created with NOAA data, click on images to enlarge ]

Deformed Jet Stream pushing more heat toward Arctic Ocean

As the Jet Stream gets more deformed due to polar amplification of the temperature rise, this can at times result in strong winds speeding up ocean currents that carry heat toward the Arctic Ocean. 

The above image, adapted from NOAA, illustrates the huge amount of heat present in the ocean around North America, with sea surface temperatures as high as 33.1°C (91.58°F) recorded on August 27, 2024.

Huge amounts of heat are carried along the path of the Gulf Stream, from the Gulf of Mexico through the North Atlantic to the Arctic Ocean. 

Local peak temperatures can be even higher. A sea surface temperature of 35.9°C (96.5°F) was recorded by station 256 in the Gulf of Mexico on August 11, 2024, as illustrated by the image below, created with cdip.ucsd.edu content. 

The image by Brian McNoldy below shows that ocean heat content in the Gulf of Mexico at record high on August 25, 2024. 

[ click on images to enlarge ]

The image on the right shows the July 2024 sea surface temperature anomaly (Northern Hemisphere view), created with a Climate Reanalyzer image. 

The image below shows a deformed Jet Stream (at 250 hPa) with many circular wind patterns. Winds merge off the North American coast, reaching speeds as high as 374 km/h (232 mph, at green circle). Such strong winds can strongly cool the sea surface due to evaporation, while forming a freshwater lid at the surface of the North Atlantic that enables more warm subsurface water to flow toward the Arctic Ocean. The image shows part of the Jet Stream moving all the way across the Arctic Ocean, speeding up ocean currents that melt the sea ice and cause further heating up of the water of the Arctic Ocean. 

While slowing down of the Atlantic meridional overturning circulation (AMOC) can hold back the flow of ocean heat toward the Arctic Ocean, at the same time more heat will accumulate at the surface of the Atlantic Ocean. Higher sea surface temperatures come with greater stratification (image below, from earlier post). 

Meltwater and rain can contribute to formation of a freshwater lid that expands at the surface of the North Atlantic. This, in combination with greater stratification (above image), can enable more ocean heat to travel underneath this lid from the North Atlantic into the Arctic Ocean, and this can occur abruptly at times when a deformed Jet Stream causes storms that speed up ocean currents along this path. The image below illustrates a cold freshwater lid forming at the surface of the North Atlantic. To a lesser extent (due to less meltwater), a lid can also form at the surface of the North Pacific along the path of the Kuroshio Current.

Arctic sea ice

The image below, adapted from the Danish Metereological Institute, shows that Arctic sea ice volume on August 31, 2024, was at a record low for the time of year, as it has been for most of the year. 

Arctic sea ice has become very thin over the years. The combination image below, created with Naval Research Laboratory images, shows a forecast for Arctic sea ice thickness on August 16, run the day before, for the years 2014, 2023 and 2024.

The image below shows sea ice disappearing over large parts of the Arctic Ocean including near the North Pole, with a NASA satellite image on the left showing the situation on August 27, 2024 and a University of Bremen images on the right showing sea ice concentration on August 26, 2024.

The screenshot below, from an earlier post, further illustrates the danger.

High methane levels over Arctic

Meanwhile, peak methane levels as high as 2414 parts per billion (ppb) were recorded by the NOAA 21 satellite at 399 mb on August 13, 2024 AM, with a global mean of 1938 ppb.

By comparison, the NOAA 20 satellite recorded peak levels as high as 2336 ppb at 487 mb on August 13, 2024 AM, with a global mean of 1943 ppb. 

As illustrated by the image below, high methane levels were recently recorded at the observatory in Barrow, Alaska. 

Climate Emergency Declaration

The situation is dire and the precautionary principle calls for rapid, comprehensive and effective action to reduce the damage and to improve the situation, as described in this 2022 post, where needed in combination with a Climate Emergency Declaration, as discussed at this group.

Links

• NASA - datasets and images
https://data.giss.nasa.gov

• Copernicus - Climate Pulse
https://pulse.climate.copernicus.eu

• Climate Reanalyzer
https://climatereanalyzer.org

• NOAA - Climate Prediction Center - ENSO: Recent Evolution, Current Status and Predictions
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

• NOAA - Monthly Temperature Anomalies Versus El Niño 

https://www.ncei.noaa.gov/access/monitoring/monthly-report/global/202407/supplemental/page-4

• Cataclysmic Alignment

https://arctic-news.blogspot.com/2022/06/cataclysmic-alignment.html

• Sunspots
https://arctic-news.blogspot.com/p/sunspots.html

• Pre-industrial
https://arctic-news.blogspot.com/p/pre-industrial.html

• Feedbacks
https://arctic-news.blogspot.com/p/feedbacks.html

• NOAA - Northern Hemisphere Ocean - Average Temperature Anomalies (1901-2000 mean) 
https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/global/time-series/nhem/ocean/1/0/1850-2024

• NOAA - Office of Satellite And Product Operations - Sea Surface Temperatures 
https://www.ospo.noaa.gov/products/ocean/sst/contour/index.html

• Coastal Data Information Program (CDIP) - Scripps Institution of Oceanography - University of California, San Diego (UCSD)

https://cdip.ucsd.edu

• Ocean Heat Content - by Brian McNoldy
https://bmcnoldy.earth.miami.edu/tropics/ohc

• Nullschool.net

https://earth.nullschool.net

• Jet Stream

https://arctic-news.blogspot.com/p/jet-stream.html

• Cold freshwater lid on North Atlantic 
https://arctic-news.blogspot.com/p/cold-freshwater-lid-on-north-atlantic.html

• Danish Meteorological Institute - Arctic sea ice volume and thickness
https://ocean.dmi.dk/arctic/icethickness/thk.uk.php

• Naval Research Laboratory, Stennis Space Center
https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/arctic.html

• NOAA 20 and NOAA 21 satellites 

https://www.ospo.noaa.gov/products/atmosphere/soundings/heap/nucaps/new/nucaps_products.html

• NOAA - Global Monitoring Laboratory - data viewer

https://gml.noaa.gov/dv/iadv/graph.php?code=BRW&program=ccgg&type=ts

• Transforming Society
https://arctic-news.blogspot.com/2022/10/transforming-society.html

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

• Climate Emergency Declaration
https://arctic-news.blogspot.com/p/climate-emergency-declaration.html

High feels like temperature forecast

Temperatures are forecast to reach 46.5°C or 115.8°F in Saudi Arabia (green circle left) and to reach 36.1°C or 96.9°F in China (green circle right) on August 4, 2024 06 UTC.

As illustrated by the image below, 'feels like' temperatures are forecast to reach 42.1°C or 107.9°F in Saudi Arabia (green circle left) and 53.6°C or 128.4°F at that location in China (green circle right), i.e. at Gaoyou, Yangzhou, Jiangsu, China, 325 km North of Shanghai, China, on August 4, 2024 06 UTC.

What makes the difference is that the 'feels like' temperature is the perceived air temperature as a combination of the heat index and wind chill. The heat index combines air temperature and relative humidity, in shaded areas. Relative humidity is forecast to be 7% in Saudi Arabia at the green circle left and 69% in China at the green circle right on August 4, 2024 06 UTC, as illustrated by the image below. 

The image below shows an even higher 'feels like' temperature of 55°C (130.9°F) that was recorded at a location 368 km north of Shanghai, China, on August 4, 2024, 09 UTC, caused by a combination of a temperature of 35.5°C (95.8°F) and a relative humidity of 75%, also resulting in a wet bulb temperature of 31.4°C (88.4°F). The image was made with a screenshot of current conditions (nowcast) at the time, but later readings show lower values (see image further below).

In hindsight, the highest 'feels like' temperature turned out to be 53.6°C (128.6°F), recorded at a location 361 km north of Shanghai, China, on August 4, 2024, 09 UTC, caused by a combination of a temperature of 35.6°C (96.2°F) and a relative humidity of 72%, also resulting in a wet bulb temperature of 31°C (87.7°F), as illustrated by the image below. 

The above image also shows wind at surface level, with a large circular wind pattern showing up south of Japan, which may have influenced conditions.  

An earlier post showed that a 'feels like' temperature of 54°C (129.1°F) hit an area west of Wuhan, China, on July 23, 2024.

High Wet Bulb Globe Temperature in California

Wet Bulb Globe Temperature takes into account the effect of temperature, relative humidity, wind speed, and solar radiation. Wet Bulb Globe Temperature is used by weather.gov to warn about extreme heat stress when in direct sunlight, as is forecast to occur in California in the grey areas on August 6, 2024 at 21 UTC. 

[ click on images to enlarge ]

The above image shows that a very high wet bulb global temperature is forecast for August 6, 2024, 21 UTC, at a location 7 miles west of Imperial, California, with the following details (inset):
- Temperature : 113°F or 45°C
- Apparent Temperature : 123°F or 51°C
- Wet Bulb Globe Temperature : 97°F or 36°C
- Dew Point : 69°F or 21°C
- Relative Humidity : 25%

Heat stress fatalities

Heat stress is the leading cause of weather-related deaths in the United States, as illustrated by the image below (credit: NOAA, text below from earlier post).

As the above image notes, the values for heat fatalities may be conservative. Research finds that where heat is being listed as an official cause of death, this likely underestimates the full toll of these events. Extreme heat can trigger heart attacks and strokes. In addition, some heart disease risk factors, such as diabetes—as well as heart medications, such as diuretics and beta blockers—can affect a person’s ability to regulate their body temperature and make it difficult to handle extreme heat. The study finds that extreme heat accounted for about 600-700 additional deaths from cardiovascular disease annually. A study estimates that extreme heat accounted for 12,000 premature deaths in the contiguous U.S. from 2000 to 2010, and an analysis calculates that the summer 2022 heatwave killed 61,000 people in Europe alone.

Temperature thresholds

As temperatures and humidity levels keep rising, a tipping point can be reached where the wind factor no longer matters, in the sense that wind can no longer provide cooling. The human body can cool itself by sweating, which has a physiological limit that was long described as a 35°C wet-bulb temperature. Once the wet-bulb temperature reaches 35°C, one can no longer lose heat by perspiration, even in strong wind, but instead one will start gaining heat from the air beyond a wet-bulb temperature of 35°C.

Accordingly, a 35°C wet-bulb temperature (equal to 95°F at 100% humidity or 115°F at 50% humidity) was long seen as the theoretical limit, the maximum a human could endure.

A 2020 study (by Raymond et al.) warns that this limit could be regularly exceeded with a temperature rise of less than 2.5°C (compared to pre-industrial). A 2018 study (by Strona & Bradshaw) indicates that most life on Earth will disappear with a 5°C rise. Humans, who depend for their survival on many other species, will likely go extinct with a 3°C rise, as illustrated by the image below, from an earlier post.

A 2022 study (by Vecellio et al.) finds that the actual limit is lower — about 31°C wet-bulb or 87°F at 100% humidity — even for young, healthy subjects. The temperature for older populations, who are more vulnerable to heat, is likely even lower. In practice the limit will typically be lower and depending on circumstances could be as low as a wet-bulb temperature of 25°C.

As temperatures rise, high 'feels like' temperatures and high wet bulb globe temperatures can be expected to occur more and more. 

Wildlife, pets, livestock and vegetation also suffer at higher temperatures. A recent study finds thresholds where vegetation productivity experiences rapid suppression, with threshold crossings occurring first of all in tropical regions. The study adds that restricting global warming to just 1.5°C can increase safe areas for vegetation growth by 13% compared to allowing warming to reach 2°C above preindustrial levels. Crop failure, loss of vegetation (and benefits such as shade) and water shortages add to the predicament of high (and rising) temperatures.

Water vapor feedback

[ from Moistening Atmosphere ]

The water vapor feedback is one of numerous self-amplifying feedbacks that accelerate the temperature rise. Just the temperature rise itself will cause more water vapor to be present in the atmosphere. Rising temperatures will result in more water vapor in the atmosphere at a rate of 7% more water vapor for every 1°C warming, and this will further amplify the temperature rise, since water vapor is a potent greenhouse gas, as discussed at the extinction page.

The February 2024 temperature was 1.76°C above 1885-1915, which could be as much as 2.75°C above the pre-industrial temperature. A 2.75°C rise corresponds with almost ⅕ more water vapor in the atmosphere.

As illustrated by the image below, created with NOAA data, surface precipitable water reached a record high of 27.395 kg/m² in July 2024. 

Climate change danger assessment

The image below, earlier discussed here, expands risk assessment beyond its typical definition as the product of the severity of impact and probability of occurrence, by adding a third dimension: timescale, in particular imminence.

Imminence alone could make that the danger constituted by rising temperatures needs to be acted upon immediately, comprehensively and effectively. While questions may remain regarding probability, severity and timescale of the dangers associated with climate change, the precautionary principle should prevail and this should prompt for action, i.e. comprehensive and effective action to reduce damage and improve the situation is imperative and must be taken as soon as possible.

Rapidly rising temperatures constitute tipping points in several ways

Firstly, there are thresholds beyond which rising temperatures become lethal for humans, as discussed above.

Secondly, some species are more vulnerable than other species. As Gerardo Ceballos describes in a 2017 analysis, there is a biological tipping point that threatens annihilation of species via the ongoing sixth mass extinction. Researchers such as Gerardo Ceballos (2020), Kevin Burke (2018) and Ignation Quintero (2013) have for years warned that mammals and vertebrates cannot keep up with the rapid rise in temperature. Humans are classified as vertebrate mammals, indicating that we will not avoid the fate of extinction, Guy McPherson (2020) adds.

Thirdly, there are further tipping points, e.g. sociopolitical ones. On the one hand, it would be good if people became more aware, as this could prompt more people into supporting the necessary action. On the other hand, as temperatures keep rising and politicians keep downplaying the dangers, there is a danger that panic will break out, dictators will grab power and civilization as we know it will collapse abruptly, as warned about earlier, e.g. in 2007.

High methane levels over Arctic Ocean

Humans will likely go extinct with a 3°C rise and one of the most-dreaded feedbacks that could contribute to such a rise is methane. Ominously, high methane levels are forecast over the Arctic Ocean for August 11, 2024, as illustrated by the image below, adapted from Copernicus. 

The above image shows a forecast for August 11, 2024, 00 UTC, at 850 hPa. High methane levels are present over the Arctic Ocean on the forecast. Note that the scale goes up to 24,840 parts per billion (ppb) for the dark red color. 

Ominously, high methane levels were also recorded recently at Barrow, Alaska. 

Climate Emergency Declaration

The situation is dire and the precautionary principle calls for rapid, comprehensive and effective action to reduce the damage and to improve the situation, as described in this 2022 post, where needed in combination with a Climate Emergency Declaration, as discussed at this group.

Links

• Nullschool
https://earth.nullschool.net

• Wet Bulb Globe Temperature
https://digital.mdl.nws.noaa.gov

• High Wet Bulb Globe Temperature Danger

https://arctic-news.blogspot.com/2024/07/high-wet-bulb-globe-temperature-danger.html

• Wet Bulb Globe Temperature Tipping Point
https://arctic-news.blogspot.com/2023/07/wet-bulb-globe-temperature-tipping-point.html

• Extreme heat stress
https://arctic-news.blogspot.com/2023/06/extreme-heat-stress.html

• Increased crossing of thermal stress thresholds of vegetation under global warming - by Xiangyi Li et al. 

https://onlinelibrary.wiley.com/doi/abs/10.1111/gcb.17406
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• Copernicus methane forecasts

https://atmosphere.copernicus.eu/charts/packages/cams/products/methane-forecasts

• Transforming Society
https://arctic-news.blogspot.com/2022/10/transforming-society.html

• Climate Plan
https://arctic-news.blogspot.com/p/climateplan.html

• Climate Emergency Declaration
https://arctic-news.blogspot.com/p/climate-emergency-declaration.html