The Paris Agreement, signed by 195 nations in 2015, pledged to keep global warming well below two degrees Celsius by the end of the century and "pursue efforts" to keep temperatures below the dangerous 1.5 Celcius target.
From July 2023 to June 2024, the world experienced the hottest temperatures on record, according to the Copernicus EU. "It must be stressed that the 1.5°C and two °C limits set in the Paris Agreement are targets for the planet's average temperature over a twenty or thirty-year period."
According to Carlo Buontempo, Director of the Copernicus Climate Change Service (C3S): "June marks the 13th consecutive month of record-breaking global temperatures, and the 12th in a row above 1.5°C with respect to pre-industrial. This is more than a statistical oddity and it highlights a large and continuing shift in our climate. Even if this specific streak of extremes ends at some point, we are bound to see new records being broken as the climate continues to warm. This is inevitable, unless we stop adding GHG into the atmosphere and the oceans. "
If you take anything away from any climate diary. Let it be this quick summary: It is that climate heating is already baked in:
Hansen's team tells us in "Global Warming in the Pipeline" that the evaluation of evidence from prehistory shows that the current modeling of equilibrium warming is understated. Equilibrium warming, or warming in the pipeline, is the ultimate temperature of Earth when our ocean and terrestrial systems come into balance with the excess greenhouse gases in our atmosphere today — with no further emissions. Even more simply, we have emitted so many greenhouse gases so much faster than they are emitted naturally that our oceans, soils, and forests are way behind in absorbing the excess, and it will take them centuries to catch up. During this "catch-up" period, we continue to warm as the cool oceans and ice sheets gradually warm to balance out with atmospheric warming. Hansen's team's new findings show that if we were to halt all emissions today magically and hold everything else stable, equilibrium warming in the pipeline in several hundred years would be 10 degrees C (18 F) above normal, and in 100 years, it is 6 to 7 C (11 to 13 F).
“This is not good news at all,” said Aditi Mukherji, a director at research institute CGIAR and co-author of the latest Intergovernmental Panel on Climate Change (IPCC) report. “We know that extreme events increase with every increment of global warming – and at 1.5C, we witnessed some of the hottest extremes this year.”
Some ecosystems are more vulnerable than others. In its latest review of the science, the IPCC found that 1.5C of warming will kill off 70-90% of tropical coral reefs, while warming of 2C will wipe them out almost entirely.
A Guardian survey of hundreds of IPCC authors this year found three-quarters expect the planet to heat by at least 2.5C by 2100, with about half of the scientists expecting temperatures above 3C. The increments sound small but can mean the difference between widespread human suffering and “semi-dystopian” futures.
Mukherji compared 1C of global heating to a mild fever and 1.5C a medium-to-high grade fever. “Now imagine a human body with [that] temperature for years. Will that person function normally any more?”
“That’s currently our Earth system,” she added. “It is a crisis.”
François Gemenne, an IPCC author and director of the Hugo Observatory at the University of Liège, said the climate crisis is not a binary issue. “It is not 1.5C or death – every 0.1C matters a great deal because we’re talking about global average temperatures, which translate into massive temperature gaps locally.”
A tiny whiff of atmospheric CO2 (0.004%) can devastate the Earth. In The Conversation, Jason West notes we should not be surprised. 'We take pills that are a tiny fraction of our body mass and expect them to affect us.'
James Hansen, Makiko Sato, Pushker Kharecha, and Leon Simons write:
“The Big Story” (titled Scorching heat wave may portend climate future) in The Hill last Thursday quoted Jonathan Overpeck, dean of the School for Environment and Sustainability at the University of Michigan, as saying, now that the El Nino has ended “we’re really looking at the next few months to tell us whether something dramatic is surprising us in the global temperatures. If it starts cooling off, [and] it hasn’t started to do that yet, we can ascribe [these] more unusual temperatures to the El Nino. If it keeps rocketing up, we’ll have to think about why climate change [is] accelerating.” [emphases are in The Hill article]
Although what Jonathan said is consistent with what some others are saying, we’re concerned about potential public misunderstanding. The world will soon start to cool off (see below), but that does not mean that we can ascribe the current unusual global heating to El Nino. Also, the rate of global warming really is accelerating (see below), even though global temperature will soon begin to decline. However, the global warming acceleration does not imply some dramatic surprise in our understanding of climate physics. The two large humanmade climate forcings – greenhouse gases (GHGs) and aerosols – account for accelerated global warming. The growth rate of these two forcings accelerated in the past 15 years.
The global warming rate since 2010 has accelerated to 0.32°C per decade, 78% faster than the 0.18°C per decade rate in 1970-2010 (Fig. 1). The impact of the acceleration on global temperature is large by 2030 (Fig. 1). Already the global anomaly of the 12-month mean temperature relative to preindustrial time is about +1.6°C (slightly less in the GISS analysis relative to 1880-1920 and slightly more than +1.6°C in other analyses relative to 1850-2000). The 12-month mean temperature is now approximately at its peak driven by the recent El Nino. The tropics, as expected, are transitioning into the La Nina state. By the end of 2024, global mean temperature will have declined significantly, but the annual 2024 global temperature should readily exceed the prior (2023) record.The El Nino/La Nina cycle is the largest cause of interannual global temperature variability. The recent El Nino was only of moderate strength and Earth’s current energy imbalance is unusually large. Thus, the global temperature decline with the budding La Nina is likely to be only about 0.2°C to about 1.4°C, so for practical purposes the Nino-average global temperature has already reached +1.5°C relative to preindustrial global temperature.
The oceans have absorbed most of the heat from the pre-industrial period to today, and the heat is now giving back.
"If we don't keep temperatures from rising above 1.5 degrees Celsius, we're in real trouble. This whole generation is doomed! I mean, that's no exaggeration." President Joe Biden, 2023
Next week's projection.
Don't lose your joy during these trying times. Do get your vengeance against the GOP and Trump this election.