Actually It Was This Hot 175,000 Years Ago

Published: July 21, 2023 8.28am EDT in The Conversation

How I imagined life was like the last it was this warm, with the help of AI

Author Darrell Kaufman, Paleoclimate Scientist, receives funding from the US National Science Foundation.

As scorching heat grips large swaths of the Earth, a lot of people are trying to put the extreme temperatures into context and asking: When was it ever this hot before?

Globally, 2023 has seen some of the hottest days in modern measurements, but what about farther back, before weather stations and satellites?

Some news outlets have reported that daily temperatures hit a 100,000-year high.

As a paleoclimate scientist who studies temperatures of the past, I see where this claim comes from, but I cringe at the inexact headlines. While this claim may well be correct, there are no detailed temperature records extending back 100,000 years, so we don’t know for sure.

Here’s what we can confidently say about when Earth was last this hot.

This is a new climate state

Scientists concluded a few years ago that Earth had entered a new climate state not seen in more than 100,000 years. As fellow climate scientist Nick McKay and I recently discussed in a scientific journal article, that conclusion was part of a climate assessment report published by the Intergovernmental Panel on Climate Change (IPCC) in 2021.

Earth was already more than 1 degree Celsius (1.8 Fahrenheit) warmer than preindustrial times, and the levels of greenhouse gases in the atmosphere were high enough to assure temperatures would stay elevated for a long time.

A time series chart shows a peak around 125,000 years ago and points to today's interglacial, showing temperatures close to the 1C warming level.
Earth’s average temperature has exceeded 1 degree Celsius (1.8 F) above the preindustrial baseline. This new climate state will very likely persist for centuries as the warmest period in more than 100,000 years. The chart shows different reconstructions of temperature over time, with measured temperatures since 1850 and a projection to 2300 based on an intermediate emissions scenario. D.S. Kaufman and N.P. McKay, 2022, and published datasets, Author provided

Even under the most optimistic scenarios of the future – in which humans stop burning fossil fuels and reduce other greenhouse gas emissions – average global temperature will very likely remain at least 1 C above preindustrial temperatures, and possibly much higher, for multiple centuries.

This new climate state, characterized by a multi-century global warming level of 1 C and higher, can be reliably compared with temperature reconstructions from the very distant past. (To continue reading go to Page 2 below)

‘Nuclear Diesel’ Could Become A Gamechanger In Energy Markets |

Advanced nuclear source energy costs can be 3.5 cents/kWh for electricity or 2 cents/kWh for high-temperature heat. This raw, source energy input cost to manufacture nuclear diesel is less than $1 per gallon. Even after adding new refinery capital costs and operations costs I expect new refineries could produce nuclear diesel at current wholesale prices near $3 per gallon.”

How Global Warming Can Start an Ice Age

ArcticColdSpotIn the last month, there’s been much attention to a cool patch in the North Atlantic Ocean, where record cold temperatures over the past eight months present a stark contrast to a globe that is experiencing record warmth. And although there is certainly no consensus on the matter yet, some scientists think this pattern may be a sign of long-feared consequences of climate change — a slowing of North Atlantic ocean circulation, due to a freshening of surface waters.

The cause, goes the thinking, would be the rapidly melting Greenland ice sheet, whose large freshwater flows may weaken ocean “overturning” by reducing the density of cold surface waters (colder, salty water is denser). If cold, salty waters don’t sink in the North Atlantic and flow back southward toward Antarctica at depth, then warm surface waters won’t flow northward to take their place.

Now, two new studies just out in Nature Geoscience help to underscore why scientists have a good reason to think this sort of thing can happen — namely, because it appears to have happened in the Earth’s distant past. And not just once but on multiple occasions.

Source: Why the Earth’s past has scientists so worried about the Atlantic Ocean’s circulation – The Washington Post

Back in 2007, I posted this sun spot research that  predicted that by 2020 we would be cooled by a low solar activity ( a cooler sun) period.   

First Direct Observation of Carbon Dioxide’s Increasing Greenhouse Effect at the Earth’s Surface

The scientists measured atmospheric carbon dioxide’s contribution to radiative forcing at two sites, one in Oklahoma and one on the North Slope of Alaska, from 2000 to the end of 2010. Radiative forcing is a measure of how much the planet’s energy balance is perturbed by atmospheric changes. Positive radiative forcing occurs when the Earth absorbs more energy from solar radiation than it emits as thermal radiation back to space. It can be measured at the Earth’s surface or high in the atmosphere. In this research, the scientists focused on the surface.

Both series showed the same trend: atmospheric COemitted an increasing amount of infrared energy, to the tune of 0.2 Watts per square meter per decade. This increase is about ten percent of the trend from all sources of infrared energy such as clouds and water vapor.

Based on an analysis of data from the National Oceanic and Atmospheric Administration’s CarbonTracker system, the scientists linked this upswing in CO2-attributed radiative forcing to fossil fuel emissions and fires.

The measurements also enabled the scientists to detect, for the first time, the influence of photosynthesis on the balance of energy at the surface. They found that CO2-attributed radiative forcing dipped in the spring as flourishing photosynthetic activity pulled more of the greenhouse gas from the air.

via First Direct Observation of Carbon Dioxide’s Increasing Greenhouse Effect at the Earth’s Surface – News Center.

"All palaeotemps" by Glen Fergus - Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons -
“All palaeotemps” by Glen Fergus – Own work. Licensed under CC BY-SA 3.0 via Wikimedia Commons – CLICK TO ENLARGE IMAGE

Climate Science Is Not Settled – WSJ

ikePolicy makers and the public may wish for the comfort of certainty in their climate science. But I fear that rigidly promulgating the idea that climate science is “settled” (or is a “hoax”) demeans and chills the scientific enterprise, retarding its progress in these important matters. Uncertainty is a prime mover and motivator of science and must be faced head-on. It should not be confined to hushed sidebar conversations at academic conferences.

Society’s choices in the years ahead will necessarily be based on uncertain knowledge of future climates. That uncertainty need not be an excuse for inaction. There is well-justified prudence in accelerating the development of low-emissions technologies and in cost-effective energy-efficiency measures.

Any serious discussion of the changing climate must begin by acknowledging not only the scientific certainties but also the uncertainties, especially in projecting the future. Recognizing those limits, rather than ignoring them, will lead to a more sober and ultimately more productive discussion of climate change and climate policies. To do otherwise is a great disservice to climate science itself.

via Climate Science Is Not Settled – WSJ.

A Simple Explanation For The Mess We Are In

So, today, you have three basic systems: order provided by democratic, inclusive governments; order imposed by autocratic exclusivist governments; and ungoverned, or chaotically governed, spaces, where rickety failed states, militias, tribes, pirates and gangs contest one another for control, but there is no single power center to answer the phone — or, if they do, it falls off the wall.

Why is this happening now? Well, just as I’ve argued that “average is over” for workers, now “average is over for states,” too. Without the Cold War system to prop them up, it is not so easy anymore for weak states to provide the minimums of security, jobs, health and welfare. And thanks to rapid advances in the market (globalization), Mother Nature (climate change plus ecological destruction) and Moore’s Law (computing power), some states are just blowing up under the pressure.

via The World According to Maxwell Smart, Part 1 –

Extreme Weather – The New Norm

The climate will swing to extremes as it tries to find a new equilibrium, in response to the warming climate. Siberian winters will be colder, heat waves extended, etc. This report says that if you are in a rainy location, expect more deluges, and if you live in a dry area, expect more droughts. Specifically, the new study found that although the 14 climate models differ when it comes to the amount of rainfall in individual locations such as cities, over larger areas, they all point to the same average picture. That is, for every single degree Fahrenheit the global average temperature climbs, heavy rainfall will increase in wet areas by 3.9 percent, while dry areas will experience a 2.6 percent increase in time periods without any rainfall.

Rain will get more extreme thanks to global warming, says NASA study | The Verge.

Video -Humongous Greenland Glacier Collapse

On May 28, 2008, Adam LeWinter and Director Jeff Orlowski filmed a historic breakup at the Ilulissat Glacier in Western Greenland. The calving event lasted for 75 minutes and the glacier retreated a full mile across a calving face three miles wide. The height of the ice is about 3,000 feet, 300-400 feet above water and the rest below water.

Chasing Ice won the award for Excellence in Cinematography at the 2012 Sundance Film Festival, and has won 24 awards so far this year. Playing in theaters now. Thanks to Valerie Sanders. Click on the YouTube logo, choose the HD option and go Full Screen for the full effect.

Return of the disparaged “Limits to Growth” Prediction

Carlton Palmer shares this gem with these comments:

Thoughtful, analysis and personal take from a Financial realist .  Civilized not a Rant! Long, Worth the effort. Ex Pat Brit.Jeremy Granthams take on the ongoing food crisis  plus the Game changer implications for the Human condition. Of note “the ethanol/gas” idiocy.

Click on the link to download the .pdf file and take the time to read this 22 page analysis

Ex Pat Brit. Jeremy Granthams take on the ongoing food crisis

The Conversion of a Climate-Change Skeptic

$150K, which was the largest funding source for this research came from the Koch foundation. The Koch brothers are billionaire conservative benefactors and probably hadn’t expected or wanted these results.

Our results show that the average temperature of the earth’s land has risen by two and a half degrees Fahrenheit over the past 250 years, including an increase of one and a half degrees over the most recent 50 years.  Why it is man-made is based simply on the close agreement between the shape of the observed temperature rise and the known greenhouse gas increase.

It’s a scientist’s duty to be properly skeptical. I still find that much, if not most, of what is attributed to climate change is speculative, exaggerated or just plain wrong. I’ve analyzed some of the most alarmist claims, and my skepticism about them hasn’t changed.Hurricane Katrina cannot be attributed to global warming. The number of hurricanes hitting the United States has been going down, not up; likewise for intense tornadoes. Polar bears aren’t dying from receding ice, and the Himalayan glaciers aren’t going to melt by 2035. And it’s possible that we are currently no warmer than we were a thousand years ago, during the “Medieval Warm Period” or “Medieval Optimum,” an interval of warm conditions known from historical records and indirect evidence like tree rings. And the recent warm spell in the United States happens to be more than offset by cooling elsewhere in the world, so its link to “global” warming is weaker than tenuous.

The careful analysis by our team is laid out in five scientific papers now online at That site also shows our chart of temperature from 1753 to the present, with its clear fingerprint of volcanoes and carbon dioxide, but containing no component that matches solar activity.

via The Conversion of a Climate-Change Skeptic –

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