Insane temperature increase next year

 From Zeke Hausfather

I'm not sure folks have realized just how crazy the second half of 2026 and 2027 will be for global temperatures – on the back of a record-smashing El Niño event. Here is my latest estimate of where both years will end up compared to global temperatures since 1850.

We're racing towards 2 degrees increase in temperatures since the 19th century.  And look how bad things already are.  The rate of increase is accelerating. 

Yet our politicians and CEOs lie to us, pretend to care, but take no action to slash emissions.  

Ocean temperatures reach June record high

From The Guardian

Temperatures on the ocean surface have hit a record high, raising fears of another burst of extreme heat this summer.

On 21 June, temperatures outside the polar regions exceeded the extraordinary highs observed at the same time in 2023 and 2024, the Copernicus Climate Change Service said on Wednesday.

It warned the new peak would probably bring “consequences for weather patterns, global climate and marine ecosystems”, not least because it would coincide with the earliest phases of an El Niño event they forecast to be the strongest in decades.

When the previous ocean record for June was set in 2023, scientists described the trends as “worrying”, “terrifying” and “bonkers” because they were so far outside their expectations. That presaged an El Niño and a period of devastating global heatwaves, floods and storms.

That 2023 record has now been surpassed and much of the world is once again seeing an alarming rise in temperatures. Last month, the UK and many other countries in Europe sweltered amid new heat records while Antarctica experienced unprecedentedly balmy winter conditions.

Although the focus is usually on land temperatures, oceans give a fuller picture of how much the climate is being pushed out of balance by human-caused warming.

Surface temperatures are affected by solar radiation, water currents and the buildup of heat in the depths.

Oceans absorb more than 90% of the excess energy in the Earth system, which is primarily caused by burning fossil fuels, such as oil, coal and gas. That imbalance hit a record 23 zettajoules last year, more than double the average of the previous two decades.

As a result, the oceans are warming at an accelerating rate. In 2020, the amount of heat being added to the oceans was equivalent to about five Hiroshima bombs a second. Last year, it was closer to 11 Hiroshima explosions a second. The UN’s secretary general, António Guterres, has warned “Earth is being pushed beyond its limits”.

Scientists said it was too early to say whether the sea surface heating would prove temporary or even worsen because annual peaks are usually registered in July and August.

But Carlo Buontempo, Copernicus director at the European Centre for Medium-Range Weather Forecasts, warned it could indicate the beginning of a new phase, leading, once more, to uncharted territory: “With ocean temperatures at these levels and El Niño on the horizon, we are likely to see more temperature records fall in the coming months.”

Copernicus is part of the EU’s space programme.

We are not helpless.  

We can replace coal and gas power stations with wind, solar and batteries to at least 90% of total electricity generation.  We can replace petrol and diesel in land transport, in cars, light trucks, and buses, and we can switch diesel trains to bi-mode trains.  We can replace oil and gas heating with electric heating and/or heat pumps.  And 40% of all shipping emissions are produced just delivering fossil fuels around the world.   

Also, you can personally change things too.  Get balcony plug-in solar.  Get home plug-in batteries.  Nag your government until they make them legal.  Vote, vote, vote.  Stop eating meat, and if that's too hard, stop eating beef and mutton.  If you can afford it, when you replace your car, get an EV.  Outside the US, their up-front cost is now as low as petrol cars, and their running costs are much lower.

And you won't be spitting into the wind, because the world's biggest carbon-emitter, China, has probably peaked its emissions.  Even in Trump's US, though abolishing the incentives to switch to green alternatives has slowed bettrification down, EV sales have started to rise, and most of new generation capacity this year is renewables.  

Fossil fuel companies and the Right want us to give up.  Don't.

It's happening—a super El Niño is coming

 

A clear and excellent explanation of El Niño, and why it's likely to be so bad this time.   Ben Miles is usually quite optimistic.  This time, he struggles to find something hopeful to say.  The world faces famine and climate disaster.  Are politicians planning for this?  Are you?  And what are we doing to reduce global heating, which is making this worse?

A humungous El Niño is on the way

From Zack Labe

Sea surface temperatures are already surging to record high levels for this time of year in key El Niño monitoring areas.

This will prolly push global temperatures towards 1.7 degrees above pre-industrial (1850-1900) levels. This is releasing heat into the atmosphere already accumulated in the sea, so it doesn't change the underlying trajectory — though it may move some world climate systems past tipping points — but it will still deliver terrible heatwaves, droughts, bushfires and floods. And meanwhile the underlying temperature is continuing to rise, and its increase appears to have been accelerating.

The January global temperature is really, really bad

 From Brian Bretschneider

Global average January temperature - color coded by ENSO status. One of these years is not like the others.

The chart shows the average January temperature for the world. Red dots show El Niño years, blue dots La Niña. During El Niño, air temperatures are higher, as heat is released from the sea. During La Niña, the reverse is true: air temperatures are cooler as more heat is absorbed by the oceans. Notice how temperatures above the trend line are mostly red dots (El Niño), while temperatures below the trend line are mostly blue dots. January 2025 is the glaring exception. It is now a La Niña phase, yet global temperatures moved to a new maximum.

click on chart to enlarge

Rise in world's temperatures accelerates

 Open Mind (Tamino) produced a previous piece about the acceleration in the rise in global temperatures, which I reported on here.  He has returned to the analysis, and confirms his position in his latest post. 

I now have global temperature data through October of this year from NASA, NOAA, and ERA5, as well as data through September from HadCRU and Berkeley. I’ve translated them to “since pre-industrial” values using one of the methods in the IPCC special report on 1.5°C. Then I computed yearly averages (this year is incomplete so values for 2024 are year-so-far averages)

There are two clear episodes in this plot: before and after 1975. Before, GMST was fluctuating but not trending either way; since, it has been trending consistenly up and fluctuating. As for its rate of increase, for four and a half decades (from 1975 until 2020) temperature seemed to rise at a pace (about 0.02°C per year) that was unchanging, and statistics couldn’t deny it.

But the last two years (2023 and 2024) have been “off the charts,” so to speak. For the data from ERA5, the value for 2024 year-so-far is already above 1.5°C, which is exactly what the Paris agreement seeks to avoid.

I investigated the rate of warming, and how it may have changed over time, in two ways. First, I fit a modified lowess smooth which I’ve programmed to estimate the rate as well as the value. Second, I computed a piecewise linear fit (PLF) with knots at 1975 and 2010. Both models (lowess and PLF) were fit to the monthly-average data, but in the graphs that follow I’ll plot yearly averages so the graphs will be less cluttered. Here’s how the PLF model fits the data from NASA:

PLF = piecewise linear fit 

 

[....]

For the 45-year period from 1975 through 2009, the average warming rate according to NASA data is just about 0.018°C/yr. For the 15-year period since 2010, it has been a lot faster at 0.031°C/yr. Statistically, the difference is significant at over 99% confidence.

I have also adjusted all the data sets, to compensate for the influence of el Niño, volcanic eruptions, and solar variations, with a method not unlike that of Foster & Rahmstorf (2011). Here are the adjusted temperatures, together with their PLF fit, for the data from NASA:

This chart shows the temperature anomaly adjusted for El Niño/La Niña and for vulcanism. 
PLF = piecewise least fit.

The rate from 1975 to 2010 now seems to be only 0.017°C/yr, and after 2010, the best estimate is 0.033°C/yr. These aren’t much different from the estimates using the raw data, although the uncertainties are now smaller so the confidence intervals are narrower.

Falling emissions (which of course we don't have--emissions continue to rise) do NOT mean that temperatures will start falling.  The RISE in the temperature anomaly is proportional to the LEVEL of emissions.  In other words, for temperatures to stop rising, we need to reduce emissions to zero.  If we halve emissions, the increase in temperature anomaly will halve, but that only reduces it to what it was before this recent acceleration, 0.17 degrees per decade.  

There are positive signs that emissions will peak soon.  Wind and solar continue to expand exponentially.  The costs of battery storage are plunging, and the recent first commercial solid-state battery points to continued and sustained cost declines and efficiency improvements.  Yet, even if we completely switch ALL electricity generation and ALL land transport to carbon-free methods, that will still only halve emissions.  If we were to start cutting emissions by 5% a year, compound, it would take us 40 years to reduce emissions to 10% of current levels.  Assuming we did this (but we are not) temperatures would rise for the next decade by 0.33 degrees, for the decade after by 0.17, by the decade after that by 0.l2 degrees and for the final decade by 0.06.  Roughly.  In other words, temperatures would rise by another 0.33+0.17+0.12+0.06, or ~0.7 degrees, making the rise since 1850-1900, the traditional "pre-industrial" starting point 2.2 degrees.

We face catastrophe, and still we dither and phaff.  The Right is dead against doing anything at all to slash emissions, and the Left argues with itself about what to do.  Meanwhile, we are lied to by corporations and governments, and protesters go to jail while oil execs are fêted.

Climate models can't explain 2023's huge heat anomaly

Source: NOAA
Note: this is relative to 1901-2000 average
Relative to the 1850-1900 average, the anomaly is already over 1.5 degrees C

From Nature, by Gavin Schmidt

When I took over as the director of NASA’s Goddard Institute for Space Studies, I inherited a project that tracks temperature changes since 1880. Using this trove of data, I’ve made climate predictions at the start of every year since 2016. It’s humbling, and a bit worrying, to admit that no year has confounded climate scientists’ predictive capabilities more than 2023 has.

For the past nine months, mean land and sea surface temperatures have overshot previous records each month by up to 0.2 °C — a huge margin at the planetary scale. A general warming trend is expected because of rising greenhouse-gas emissions, but this sudden heat spike greatly exceeds predictions made by statistical climate models that rely on past observations. Many reasons for this discrepancy have been proposed but, as yet, no combination of them has been able to reconcile our theories with what has happened.

For a start, prevalent global climate conditions one year ago would have suggested that a spell of record-setting warmth was unlikely. Early last year, the tropical Pacific Ocean was coming out of a three-year period of La Niña, a climate phenomenon associated with the relative cooling of the central and eastern Pacific Ocean. Drawing on precedents when similar conditions prevailed at the beginning of a year, several climate scientists, including me, put the odds of 2023 turning out to be a record warm year at just one in five.

El Niño — the inverse of La Niña — causes the eastern tropical Pacific Ocean to warm up. This weather pattern set in only in the second half of the year, and the current spell is milder than similar events in 1997–98 and 2015–16.

However, starting last March, sea surface temperatures in the North Atlantic Ocean began to shoot up. By June, the extent of sea ice around Antarctica was by far the lowest on record. Compared with the average ice cover between 1981 and 2010, a patch of sea ice roughly the size of Alaska was missing. The observed temperature anomaly has not only been much larger than expected, but also started showing up several months before the onset of El Niño.

So, what might have caused this heat spike? Atmospheric greenhouse-gas levels have continued to rise, but the extra load since 2022 can account for further warming of only about 0.02 °C. Other theories put forward by climate scientists include fallout from the January 2022 Hunga Tonga–Hunga Ha‘apai volcanic eruption in Tonga, which had both cooling effects from aerosols and warming ones from stratospheric water vapour, and the ramping up of solar activity in the run-up to a predicted solar maximum. But these factors explain, at most, a few hundredths of a degree in warming (Schoeberl, M. R. et al. Geophys. Res. Lett. 50, e2023GL104634; 2023). Even after taking all plausible explanations into account, the divergence between expected and observed annual mean temperatures in 2023 remains about 0.2 °C — roughly the gap between the previous and current annual record.

There is one more factor that could be playing a part. In 2020, new regulations required the shipping industry to use cleaner fuels that reduce sulfur emissions. Sulfur compounds in the atmosphere are reflective and influence several properties of clouds, thereby having an overall cooling effect. Preliminary estimates of the impact of these rules show a negligible effect on global mean temperatures — a change of only a few hundredths of a degree. But reliable assessments of aerosol emissions rely on networks of mostly volunteer-driven efforts, and it could be a year or more before the full data from 2023 are available.

This is too long a wait. Better, more nimble data-collection systems are clearly needed. NASA’s PACE mission, which launched in February, is a step in the right direction. In a few months, the satellite should start providing a global assessment of the composition of various aerosol particles in the atmosphere. The data will be invaluable for reducing the substantial aerosol-related uncertainty in climate models. Hindcasts, informed by new data, could also provide insights into last year’s climate events.

But it seems unlikely that aerosol effects provide anything close to a full answer. In general, the 2023 temperature anomaly has come out of the blue, revealing an unprecedented knowledge gap perhaps for the first time since about 40 years ago, when satellite data began offering modellers an unparalleled, real-time view of Earth’s climate system. If the anomaly does not stabilize by August — a reasonable expectation based on previous El Niño events — then the world will be in uncharted territory. It could imply that a warming planet is already fundamentally altering how the climate system operates, much sooner than scientists had anticipated. It could also mean that statistical inferences based on past events are less reliable than we thought, adding more uncertainty to seasonal predictions of droughts and rainfall patterns.

Much of the world’s climate is driven by intricate, long-distance links — known as teleconnections — fuelled by sea and atmospheric currents. If their behaviour is in flux or markedly diverging from previous observations, we need to know about such changes in real time. We need answers for why 2023 turned out to be the warmest year in possibly the past 100,000 years. And we need them quickly.

Nature 627, 467 (2024)

doi: https://doi.org/10.1038/d41586-024-00816-z

We face a climate catastrophe.  And we are still doing too little to stop it.

2024 likely to be another record year, despite La Niña

From Discover Magazine

As La Niña continues to stir in the tropical Pacific Ocean, the latest analysis shows there’s a 70 percent chance it will develop between August­ and October.

The climate phenomenon shifts the world's atmospheric circulation, changing weather patterns around the globe. Characterized by cooler-than-average sea surface waters in large swaths of the tropical Pacific, it also usually takes the edge off human-caused heating of the planet, albeit temporarily.

But even taking that likely cooling effect into account, a new annual global heating record is very likely in 2024, according Gavin Schmidt, director of NASA's Goddard Institute for Space Studies.

Schmidt made the prediction on the Bluesky social media platform after his institute's analysis showed last month to be the warmest June on record. It was also the 13th straight month with record-breaking global temperatures. (Other analyses have shown the same, including one released by NOAA today.)

Last year shattered the record for the hottest year globally since record-keeping began in the 1800s. With an El Niño adding to the global heating caused by our continuing emissions of greenhouse gases, a new record in 2023 should not have come as a surprise. But the heat over land and in the seas was so extreme that scientists were nonetheless shocked — and they're still working hard to understand the details of what happened.

Warming rate probably accelerating

 Another in depth statistical analysis from Open Mind (Tamino).  I won't repeat the whole article (best to read it for yourself).   In essence, what he does is look at the change in the temperature anomaly over 30 years, the conventional measure of climate change (because shorter periods are too susceptible to fluctuations from natural climate cycles such as, for example, El Niño/La Niña).    This chart shows what that looks like:

Note that the change over the 30-year span has been centred at 15 years,
which is why it apparently ends at 2009.

He then adjusts the data for volcanic eruptions, El Niño, and the sunspot cycle to test whether the change in trend since 2000 is statistically significant, and concludes that it is.

But wait, there’s more. We know the cause of some of the fluctuation, and we can adjust the data by removing our best estimate of those known factors. In particular, we can remove an estimate of the influence of volanic eruptions, solar variations, and the el Niño southern oscillation, and I’ve done so by a modified version of the method of Foster & Rahmstorf.

Comparing this graph of adjusted data since 1946, to the graph of raw data over the same time (the third graph in this post), two things are obvious. First, the level of scatter (of random fluctuation) is quite a bit less for the adjusted data than for the raw. Second, the “obvious” simple model for the raw data (a linear spline with two straight-line setments) isn’t so obvious for the adjusted data.

The same analysis used on the raw data, returns different results on the adjusted. This is mainly because the uncertainty levels are so much reduced. The warming rate for NASA data, for example, now looks like this:

Again, the change has been centred midway on the 30-year span

The final 30-year estimate suggests the rate was definitely bigger then 0.02°C/year, while the earlier rate is definitely less. Also, the statistical tests (fitting a parabola and a linear spline) now are definitely significant at 95% confidence.

Using adjusted rather than raw data, the same is true for all five data sources. While the significance is weakest for HadCRU and strongest for NOAA, it’s over 95% confidence for all of them. My conclusion is that recent acceleration of global warming isn’t just likely, it’s confirmed.

There is still room for doubt, if you doubt that the adjusted data represent things correctly then the recent apparent acceleration may be just random accident. All told, I find that too unlikely.

See also this piece I did, based on Open Mind's analysis: 

Terrifying acceleration in global heating

We are heading towards climate catastrophe, and still we do not act, stumbling blindly to the precipice.

Is global heating accelerating?

 From Just Have a Think

See also:   

Terrifying acceleration in global heating

Amazon's record drought driven by climate change

From The BBC

One of our planet's most vital defences against global warming is itself being ravaged by climate change.

It was the main driver of the Amazon rainforest's worst drought in at least half a century, according to a new study.

Often described as the "lungs of the planet", the Amazon plays a key role in removing warming carbon dioxide from the atmosphere.

But rapid deforestation has left it more vulnerable to weather extremes.

While droughts in the Amazon are not uncommon, last year's event was "exceptional", the researchers say.

In October, the Rio Negro - one of the world's largest rivers - reached its lowest recorded level near Manaus in Brazil, surpassing marks going back over 100 years.

As well as being a buffer against climate change, the Amazon is a rich source of biodiversity, containing around 10% of the world's species - with many more yet to be discovered.

The drought has disrupted ecosystems and has directly impacted millions of people who rely on rivers for transport, food and income, with the most vulnerable hit hardest.

One trigger for these dry conditions is El Niño - a natural weather system where sea surface temperatures increase in the East Pacific Ocean. This affects global rainfall patterns, particularly in South America.

But human-caused climate change was the main driver of the extreme drought, according to the World Weather Attribution group, reducing the amount of water in the soil in two main ways.

Firstly, the Amazon is typically receiving less rainfall than it used to between June and November - the drier part of the year - as the climate warms.

Secondly, hotter temperatures mean there's more evaporation from the plants and soils, so they lose more water.

The researchers used weather data and computer simulations to compare drought conditions in two scenarios: one with human-caused warming, and one without.

In a world where humans hadn't heated up the planet by around 1.2C, such an intense 'agricultural drought' - where a lack of rainfall and high evaporation dry out the soils - may only have happened around once every 1,500 years, the study suggests.

Climate change has made a drought of this severity around 30 times more likely, according to the researchers, and one is now expected to happen every 50 years under current conditions.

"This really is something quite exceptional," says Dr Ben Clarke, a researcher with the World Weather Attribution group.

And if warming continues, such extreme droughts could become even more common.  "If we continue burning oil, gas and coal, very soon, we'll reach 2C of warming and we'll see similar Amazon droughts about once every 13 years," says Dr Friederike Otto, a senior lecturer in climate science at Imperial College London.

More frequent and intense droughts test the Amazon's resilience. That has already been stretched by deforestation - around one-fifth of the rainforest has been lost over the last 50 years.

Trees help the area retain and release moisture, fuelling their own clouds, and they also help to cool temperatures.

While the effect of deforestation was not directly tested in this latest study, previous research has shown it increases the vulnerability of the rainforest to drought.

The world's largest rainforest is seen as crucial in the battle to limit global warming.

"The Amazon could make or break our fight against climate change," says Regina Rodrigues, a professor of physical oceanography and climate at the Federal University of Santa Catarina in Brazil.

In a healthy state, it takes up more carbon dioxide (CO2) than it releases.

This limits CO2 increases in the atmosphere from human activities, keeping a lid on temperatures.

But there is evidence that this may be changing, as trees die back due to drought, wildfires and deliberate clearance to make room for agriculture.

There is concern that if climate change and deforestation continue at their current pace, the Amazon could soon reach a "tipping point".

If crossed, this could lead to the rapid and irreversible dieback of the whole rainforest - potentially leading to the region becoming a significant source of CO2 emissions.

It's not known exactly where such a threshold might sit.

"I don't think that [tipping point] is what we are seeing [yet], at least in all but the driest part of the Amazon forest," says Yadvinder Malhi, a professor of ecosystem science at the University of Oxford, who was not involved in the latest study.

This - alongside urgent action to slash the greenhouse gas emissions that are fuelling global warming - can still help to protect what's left of the Amazon, researchers say.

"The loss of the Amazon forest is far from inevitable in the short-term," as long as fire and deforestation can be controlled, Prof Malhi told BBC News.

"But we do need to get to grips with stabilising global climate, as the risk increases with every fraction of a degree the planet warms."

Global temperatures rising again

Despite three years of La Niña, global temperatures have started rising again.  This year, the world will experience an El Niño, and temperatures will rise as they always do during El Niños.  The chart shows the temperature anomaly relative to the 1901-2000 average.    The years from 1850 to 1900 were on average something like 0.2 degrees cooler, so a 1.5 degrees increase above pre-industrialisation temperatures would be reached when the red bars reach 1.3 degrees C on the chart.   Note the LOESS smoothing and its steady and inexorable rise.

The last El Niño peak was in 2016, with the anomaly reaching 1.14 degrees C.   Temperatures are rising by roughly 0.2 degrees C per decade, so a temporary El Niño peak of 1.3 degrees C above the 1901-2000 average in 2024 is plausible.   (The rise between the 1998 and 2016 El Niños was 0.44 degrees C).  And that would mean we would have (temporarily) breached the 1.5 degree guardrail for the first time in recorded history.

Temperatures won't stop rising until CO2 emissions fall to zero or close to that, though we might get a temporary respite if methane emissions are slashed.  However, both CO2 and CH4 emissions continue to rise.

Too little is being done to prevent catastrophe.

Source: NOAA

Ocean Temperatures off the charts

From The Guardian

The temperature of the world’s ocean surface has hit an all-time high since satellite records began, leading to marine heatwaves around the globe, according to US government data.

Climate scientists said preliminary data from the National Oceanic and Atmospheric Administration (NOAA) showed the average temperature at the ocean’s surface has been at 21.1C since the start of April – beating the previous high of 21C set in 2016.

“The current trajectory looks like it’s headed off the charts, smashing previous records,” said Prof Matthew England, a climate scientist at the University of New South Wales.

Three years of La Niña conditions across the vast tropical Pacific have helped suppress temperatures and dampened the effect of rising greenhouse gas emissions.

But scientists said heat was now rising to the ocean surface, pointing to a potential El Niño pattern in the tropical Pacific later this year that can increase the risk of extreme weather conditions and further challenge global heat records.

Dr Mike McPhaden, a senior research scientist at NOAA, said: “The recent ‘triple dip’ La Niña has come to an end. This prolonged period of cold was tamping down global mean surface temperatures despite the rise of greenhouse gases in the atmosphere.

“Now that it’s over, we are likely seeing the climate change signal coming through loud and clear.”

La Niña periods – characterised by cooling in the central and eastern tropical Pacific and stronger trade winds – have a cooling influence on global temperatures. During El Niño periods, the ocean temperatures in those regions are warmer than usual and global temperatures are pushed up.

According to the NOAA data, the second-hottest globally averaged ocean temperatures coincided with El Niño that ran from 2014 to 2016.

The data is driven mostly by satellite observations but also verified with measurements from ships and buoys. The data does not include the polar regions.

More than 90% of the extra heat caused by adding greenhouse gases to the atmosphere from burning fossil fuels and deforestation has been taken up by the ocean.

A study last year said the amount of heat accumulating in the ocean was accelerating and penetrating deeper, providing fuel for extreme weather.

England, a co-author of that study, said: “What we are seeing now [with the record sea surface temperatures] is the emergence of a warming signal that more clearly reveals the footprint of our increased interference with the climate system.”

Measurements from the top 2km of the ocean show the rapid accumulation of heat in the upper parts of the ocean, particularly since the 1980s.

Dr Kevin Trenberth, a climate scientist and distinguished scholar at the US National Center for Atmospheric Research, said observations showed the heat in the tropical Pacific was extending down to more than 100 metres.

He said that heat would have knock-on effects for the atmosphere above, creating more heat, adding energy to weather systems and causing marine heatwaves.

Dr Alex Sen Gupta, an associate professor at the UNSW Climate Change Research Centre, said satellites showed that on the ocean surface, temperature rises had been “almost linear” since the 1980s.

“What’s been surprising is that the last three years have also been really warm, despite the fact that we’ve had La Niña conditions,” he said. “But it is now warmer still and we are getting what looks like record temperatures.”

 

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2023 likely to be hotter than 2022

2022 was a La Niña year, when global temperatures are temporarily reduced as part of the El Niño-Southern Oscillation (ENSO).  Most meteorologists are forecasting that 2023 will not be another La Niña year, but at this stage, it doesn't look like it will be an El Niño year, when temperatures reach new records.  (See the 1998 and 2016 El Niño years in NOAA's chart below)  So, prolly, higher temperatures on average, but not extreme.

The trend over the last 50 years is a rise of 0.18 degrees C per decade.  The rise in temperatures is proportional not to the rise in emissions, but to the level of emissions.  Emissions are levelling off (sort of), thanks to Covid, recessions, and the inexorable rollout of renewables. But to reduce the decadal increase in global temperatures to, say, 0.1 degrees, we will need to halve emissions.  And then, to get close to a zero decadal rise, we will need to halve them again.  It would be nice if we halved them over the next decade and halved them again in the 2040s.  But we prolly won't, despite some partial good news.

Source: NOAA

Shifts in El Niño-La Niña cycle fuelling climate extremes

 From Inside Climate News

The record-breaking heat wave last week in East Antarctica, the coldest region on Earth, saw temperatures surge as much as 85 degrees Fahrenheit above average, bringing readings near freezing and unexpected surface melting instead of the usual sub-zero conditions.

The heat wave adds to a quickly growing list of previously “unthinkable” climate events, and puts an exclamation point on an Austral summer that included brutal heat waves and record-high intensity wildfires in Argentina and Chile and flooding caused by record-setting rains in eastern Australia that killed more than 20 people and left thousands homeless.

Other “unthinkable” extremes hit the Northern Hemisphere in the months before that. A December wildfire in the Rocky Mountain foothills of Colorado completely changed how some forest and fire scientists see the fire risk in that area, and the Pacific Northwest heat wave that started in June 2021 was an extreme not forecast by climate models. As that heat wave ebbed in July, parts of several German towns were destroyed by flooding rainstorms that were intensified by global warming. And in recent days, temperatures surged to 50 degrees Fahrenheit in the Siberian Arctic near the North Pole and above the adjacent Arctic Ocean.

Scientists exploring possible connections between the remarkable series of extremes in both hemispheres say they are increasingly certain that the powerful El Niño-La Niña cycle in the Pacific Ocean is one of the key links. New research shows the cycle has shifted in a way that is likely to fuel extremes, including wild swings between heat and drought and flooding rains.

In the El Niño/Southern Oscillation (ENSO), huge masses of water surge eastward and westward every two to seven years along a vast region of the equatorial Pacific. One of the strongest El Niños on record in 2016 helped boost the average global temperature to a new record high that year.

It’s Happening. Now. The most recent global science report from the Intergovernmental Panel on Climate Change projected that the global warming fingerprint on the El Niño-La Niña cycle would become apparent after about 2050. But the accelerating pace of record-breaking weather events shows that the destructive effects are already here, said Wenju Cai, director of the Center for Southern Hemisphere Oceans Research at the Commonwealth Scientific and Industrial Research Organisation in Australia.

Cai was a co-author on a key 2022 study showing that the western Pacific is warming more than the eastern Pacific and that the growing temperature contrast is driving complex changes to the El Niño cycle, but Cai said some key climate signals are emerging, including enhanced rainfall in the areas favored by the respective phases of the cycle. And along with the background global warming, each major El Niño peak since the 1950s has been stronger than the previous, pushing ocean surface temperatures to new highs in the east-central equatorial Pacific, where important climate measurements are made.

“Anything that happens in the tropics affects both the northern and southern hemisphere,” Cai said, adding that, as the El Niño/Southern Oscillation changes, the affected areas are expanding and the extremes are intensifying and lasting longer in both hemispheres.

How global warming changes the El Niño cycle is a “fundamental issue in climate science with critical societal ramifications” because the cycle is so important to driving climate extremes “within and outside the Pacific,” Cai and his co-authors wrote in the study, published in January in Nature Climate Change.

There is not yet a discernible direct link between the current La Niña phase of the cycle and the recent heat wave in the Antarctic: Researchers have not even begun to explore a connection. But the southern polar extreme happened just days after scientists announced the finding that Antarctic sea ice had plummeted to the lowest extent on record, leaving miles of open ocean that’s darker and warmer than a reflective ice shield. And recent research suggests that the El Niño cycle affects Antarctic ice shelves, with more melting from below in their floating sections, but also with increased snowfall on the surface that can thicken the ice.

The warm air streaming from the direction of Australia over East Antarctica also dumped record amounts of rain and snow, adding 65 gigatons of mass to the ice sheet in three days (March 16 to 18), said University of Liege polar researcher Xavier Fettweis.

“Usually, the climate of Antarctica is too cold to have significant accumulation of snow, and most of liquid water from melt or rainfall is absorbed by the snowpack and refreezes,” he said. Under very warm and wet air mass that moved over Antarctica “the ice sheet gained 69 gigatons in three days, three times the usual surface mass gain rate.”

During the El Niño phase of the cycle, warmer than average water sloshes toward the eastern equatorial Pacific, often spurring intense winter precipitation along the West Coast of North America and North America, with relatively cooler water in the western Pacific—conditions that contributed to the 2019-2020 Black Summer fires in Australia.

When the cycle flips to La Niña, as in the last couple of years, the eastern and central equatorial Pacific cool, and parts of the eastern Pacific, known as the ocean warm pool, heats up even more, with broad climate patterns favoring extremes like Australia’s March floods and drought in the southwestern United States.

Oceans hold 93 percent of the heat trapped by greenhouse gasses, and the tropical Pacific is the biggest tank for this heat, pure energy for the climate system. The El Niño-La Niña cycle is the pump distributing that energy, as heat and moisture, to the global climate system, to the east and west of the equator, as well as the north and south.

Matt England, who studies climate extremes at the University of New South Wales, said that even a decade ago he would not have expected to see impacts from the intensification of La Niña—like the March flooding in Australia—to show up so soon. But it’s not surprising that the effects are being felt in both hemispheres, he said.

“The ENSO cycle definitely involves large-scale reorganization of the global atmosphere, across both hemispheres, north and south, but also east and west,” England said, “It is one of the primary drivers of these climate extremes we’ve been seeing, the classic signature being floods and drought and fire,” shifting between the Americas and Indonesia, Australia and other western Pacific nations, depending on the phase of the cycle,” he added.

The north-south influence of a changing El Niño/Southern Oscillation cycle is harder to see, he said, “because ENSO is mainly about pushing water back-and-forth in an east and west sense along the tropical Pacific.”

Along with the east-west ocean shifts, ENSO generates huge areas of convective moist air that rise and shift around, almost like bubbles in a lava lamp. They’re big enough to push around wind belts that carry seasonal rain and snow storms and warm and moist enough to give those storms an extra kick, he said.

In one example of how the effects ripple globally in both hemispheres, the United States Agency for International Development (USAID), an independent U.S. government agency that delivers international aid, reported last month that La Niña and climate change are causing exceptional drought in East Africa,

England said that the effect on Antarctic sea ice is complex, and he noted that long-term climate records from the remote region are few and far between. But it appears that La Niña phases lead to a lower extent of sea ice. Stronger La Niñas could mean more years of record-low Antarctic sea ice, and every time that happens, the ocean warms a bit more, making it harder for the sea ice to form again the following winter, he added.

His advice: Hang on tight for the climate roller coaster ahead.

“Earth’s climate has ways of reorganizing itself in rapid and highly nonlinear ways and El Niño is part of that,” he said. “What concerns climate scientists is that these are not always small and gradual shifts.”

Temperatures have been rising for 100 years

 Global temperatures have been rising for over a hundred years, though the faster rise only began from the 1970s onwards.  This coincided with a steady expansion in CO2 and other greenhouse gas emissions, which accelerated after WW2 and again with the rise of China.   Note 1) the occasional random spikes up, and down; 2) cycles around the rising trend caused by such natural cycles as ENSO  (El Niño Southern Oscillation); 3) occasional 2-3 year blips caused by volcanic eruptions (for example after the Mt Pinatubo eruption in 1991).  

Temperatures have drifted lower since the last El Niño, in 2016, just as they did in the one before in 1998.  The post 1998 decline led many to conclude that global temperatures had stopped rising, though that notion was dispelled when the next ENSO cycle came along.  Over the next couple of years, the volcanic eruption in Tonga will likely cool the Earth by at least 0.5 degrees, because of the emission of sulphur dioxide aerosols.

(Chart from  Our World in Data)

Last 7 years hottest ever

 From NOAA

Source: NOAA

Cooler than it was in 2020, because it was a La Niña year.  A fair bit cooler than 2016, an El Niño year, when the Pacific gives up some of the heat it has absorbed during the La Niña.  Still, the last 7 years have been the warmest measured by thermometer in the last nearly 150 years, and, using numerous proxy measurements, the hottest in the last 2000.  Temperatures will drop over the next couple of years because of the massive eruption of the volcano in Tonga.  No doubt, denialists will have a field day, pointing out that temperatures have fallen since 2016.   After all, after the last big El Niño in 2008, they dined out for years on the fact that temperatures had "stopped rising", ignoring the ENSO  (El Niño- Southern Oscillation) cycles.

Optimistic?

 I alternate between deep pessimism about the climate emergency and cautious optimism.

The reasons for pessimism are obvious. So why the cautious optimism?

The answer lies in the plunging costs of renewables and batteries. It was always hard to urge poor countries to embrace renewables when they cost more than fossil fuels. So while some rich countries used subsidies and directives to encourage the growth of renewables―Germany's emissions, for example, are now back at 1950s levels―poor countries were prolly not going to follow suit.

But all that's changed. Renewables are now cheaper than fossil fuels in most of the world, and the rapid decline in the cost of batteries (halving every 3 years) means that 'firming' the output of wind and solar farms is becoming cheaper and cheaper. What's more, greening electricity supply was the hardest part of decarbonising, and it's now the easiest part. At the same time, because electricity production is becoming greener, as electric vehicles get cheaper, the world's car and lorry and bus fleets will progressively move to EVs. Electricity generation contributes ~30% of CO2 emissions, land transport ~20%. Which means the world could actually get close to halving emissions by 2035, even before we start on iron and steel, cement, agriculture and chemical manufacturing.

Whatever the Republicans and other denialists like Australia's National Party MP,  David Littleproud think, the fact is that demand for coal, and eventually gas, too, will fall. This will happen whatever posturing and virtue signalling right-wing denialists do. Their pig-headedness has consequences, though. Coal communities are being lied to. Coal cannot be saved. Planning should start now for an orderly transition, for development programs that create jobs to replace those lost.

Source:NOAA

Global temperatures are rising by 0.2 degrees C every decade. If we get close to zero emissions by 2050, that rate of increase should slow, although there are lags in the system. But, because of feedbacks and tipping points, such as the elimination of Arctic sea ice, even after man's CO2 emissions have reached zero, temperatures could continue to rise. By 2050, the chances are that global temperatures will on average be at least 0.6 degrees C higher than they are now. And we are already 1 deg C above the 1900-1999 average. Not good.  The consequences of  the rise we have already seen are obvious.  How bad will a rise of another 0.6 or 0.8 or 1 degree C be?  Average global temperatures in September were the highest ever recorded for that month, while the year to September was the second highest, even though there is a La Niña occurring. We're running out of time.

So, cautiously optimistic, despite the half-witted convulsions of the Right, because economics is on our side now. The thing is, we need to achieve zero carbon sooner than 2050, if we are to avoid a disastrous rise in global temperatures.  And although the economics of renewables favour a rapid transition, powerful vested interests are very happy with the status quo, and would like to delay the shift to zero carbon as long as possible.  Hence the pessimism.

No El Niño, yet hottest January ever

The last El Niño was in 2015/16.  During an El Niño event, heat that has been previously absorbed by the ocean is re-released into the atmosphere, raising average atmospheric temperatures.  So for temperatures to exceed El Niño levels in a normal year is a pretty big deal.  That's what's just happened.  January was the hottest January ever recorded.

Source: NOAA

The average for the 12 months to January is now just a whisker below the 2016 record.  Even though we are NOT having an El Niño. 

Source: NOAA

Over the last decade, the increase in the global temperature anomaly was 0.3 degrees.  If that continues, by 2050 temperatures will have risen another 0.9 degrees C, or basically 2 degrees since the beginning of the industrial revolution.  It might not continue, but an acceleration of the rate of increase  would be consistent with the continued rise in emissions.  The 1 degree rise we have already seen has had severe consequences.  No one knows how bad 2 degrees will be.  What's more, temperatures will go on rising until emissions reach zero.  In fact they may go on rising for a couple of decades even after emissions reach zero because of the lags in the climate system.

If we cut emissions by 5% per year cumulative, they'll have fallen 80% by 2050 and 95% by 2070, which would mean that by 2070, temperatures will have risen 2.5 degrees since before the industrial revolution began.  This is flirting with catastrophe.  We need to do better.  Much better.

And emissions aren't falling.  And by the time they are, the annual percentage reduction will have to be higher than 5%.  Every year we delay, every lie by a fossil fuel advocate, every bit of greenwashing by a politician or a company just makes the ultimate adjustment harder.

2017 hottest year adjusting for ENSO

2017 was marginally cooler than 2016, which was an El Niño* year.  The fall from 2016 was much less than the decline after the last El Niño in 1998**.  The chart below shows the temperature record adjusted for El Niños.  Adjusting for the impact of El Niños, 2017 was the hottest year.  Note how major volcanic eruptions cause temperatures to drop for a couple of years.  This is because eruptions release particulates (mostly sulphur dioxide) into high altitudes, which reflect incoming solar radiation.  If you fitted a long-term moving trend to the data from 1950 onwards you would get a steadily rising curve:  the rate of increase in temperatures appears to be accelerating.

[Read more here]

* ENSO stands for El Niño Southern Oscillation

** a favourite start year for denialists wanting to "prove" that temperatures haven't risen over the last X years.