The Hothouse Horror (Ho Hum)

A new paper published in the Proceedings of the National Academy of Science (PNAS) speculates on major warming in our future. It has sent the gullible, alarmist press into a twitter of claiming that we must do something immediately. Trouble is, this very speculative paper says major warming may, might, could, perhaps occur sometime within the next few centuries to thousands of years.

Here is the abstract:

We explore the risk that self-reinforcing feedbacks could push the Earth System toward a planetary threshold that, if crossed, could prevent stabilization of the climate at intermediate temperature rises and cause continued warming on a “Hothouse Earth” pathway even as human emissions are reduced. Crossing the threshold would lead to a much higher global average temperature than any interglacial in the past 1.2 million years and to sea levels significantly higher than at any time in the Holocene. We examine the evidence that such a threshold might exist and where it might be. If the threshold is crossed, the resulting trajectory would likely cause serious disruptions to ecosystems, society, and economies. Collective human action is required to steer the Earth System away from a potential threshold and stabilize it in a habitable interglacial-like state. Such action entails stewardship of the entire Earth System—biosphere, climate, and societies—and could include decarbonization of the global economy, enhancement of biosphere carbon sinks, behavioral changes, technological innovations, new governance arrangements, and transformed social values. [full paper here]


What? Me worry? Dr. Judith Curry (retired Professor and Chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology) opines: “A paper about climate outcomes on a millennial time scale would seem to be completely irrelevant to any conceivable policy. Even if our understanding of all of these climate processes were certain (reality check: we are dealing with deep uncertainty with regards to future climate outcomes), geologic and solar wild cards will almost certainly come into play to produce climate surprises.”

The horrid hothouse described in the paper is actually the normal temperature for planet Earth according to geological evidence (except during ice ages). Current global average surface temperature is about 57°F (14°C) versus a “normal” temperature of 77°F (25°C) as shown on the graphic below:


During times of “normal” (very warm) temperatures life was abundant and robust. If (or when) we return to those temperatures we will have to adapt as it gets warmer and sea level rises.

My impression of this paper is that its sixteen co-authors are taking advantage of the political climate to get their names on a paper published in a professional journal, something very important to academics.

On the other hand, we might first have to adapt to colder temperatures. Scientists who pay attention to solar cycles have noticed that the magnetic strength of the sun is declining with each cycle. This means that more cosmic rays will enter the atmosphere and produce more clouds and hence more cooling. The graphic below shows the gradual decline of temperature during our current inter-glacial period and the cyclic nature of warm-cold periods. Speculation is that we are about to enter one of the cold spells of the Holocene or even that the relatively benign inter-glacial period is coming to an end.

Here is an example:

The Next Ice Age

By Dr. S. Fred Singer

While most people still worry about global warming, I am more concerned about the next Ice Age. A glaciation would present a serious problem for survival of our present civilization, akin to a nuclear winter that many worried about 30 years ago.

Natural warming of the Earth reached a peak 65 million years ago. The climate has been generally cooling ever since. Antarctic ice sheets started growing 25 million years ago. In the last 2.5 million years, the Earth entered the period of Ice Ages [the geological name is The Pleistocene] and has been experiencing periodic glaciations where much of the land was covered by miles-thick ice sheets.

There have been about 17 glaciations, each lasting approximately 100,000 years, separated by short inter-glacials lasting about 10,000 years.

We are approaching the likely end of the present warm inter-glacial, called the Holocene. It’s time to prepare for the next glaciation to see how we can overcome it – or at least postpone its onset. Read more (Singer is a physicist and a Professor emeritus of environmental science, University of Virginia.) I’m with Fred.

If Dr. Singer is right, then we all should triple our “carbon footprints” assuming you believe that carbon dioxide emissions play a significant role in controlling global temperature.

An article in Science 2.0: “Not As Scary As It Seems: Planet At Risk Of Heading Towards “Hothouse Earth” State” [link] Gives a summary and comments on the paper. They say “Hothouse earth does not make us extinct – still a very habitable planet” and “In short, it is a hypothesis not yet supported by evidence.”


Solar cycle changes indicate a cooling period ahead

The British Meteorological Office (the MET) is predicting the end of our current solar cycle warm phase which portends cooler temperatures during the next 40 years. Here are some comments from several organizations:


Daily Mail: Met Office’s Hadley Centre, which looks at long term forecasts, said there was a 15-20 per cent chance that we could match the temperatures last seen in 1645-1715 – sometimes called the Little Ice Age – when the River Thames froze over. This could take place at some point within the next 40 years. The prediction is based on counting sun spots – dark patches on the sun – that are hot spots and signs of increased solar activity.

Nature Communications: The past few decades have been characterized by a period of relatively high solar activity. However, the recent prolonged solar minimum and subsequent weak solar cycle 24 have led to suggestions that the grand solar maximum may be at an end. Using past variations of solar activity measured by cosmogenic isotope abundance changes, analogue forecasts for possible future solar output have been calculated. An 8% chance of a return to Maunder Minimum-like conditions within the next 40 years was estimated in 2010. The decline in solar activity has continued and is faster than any other such decline in the 9,300 years covered by the cosmogenic isotope data. If this recent rate of decline is added to the analysis, the 8% probability estimate is now raised to between 15 and 20%.

Daily Caller: A new study out of the United Kingdom predicts the Earth is about to go through a major climatic shift that could mean decades of cooler temperatures and fewer hurricanes hitting the United States. Scientists at the University of Southampton predict that a cooling of the Atlantic Ocean could cool global temperatures a half a degree Celsius and may offer a “brief respite from the persistent rise of global temperatures,” according to their study. Atlantic cooling can impact the climate for decades, according to researchers, on time scales from 20 to 30 years. This means cooler global temperatures and changing weather patterns could unfold over the next two to three decades, possibly extending the so-called “pause” in global warming.

Vencore Weather: The sun is almost completely blank. The main driver of all weather and climate, the entity which occupies 99.86% of all of the mass in our solar system, the great ball of fire in the sky has gone quiet again during what is likely to be the weakest sunspot cycle in more than a century. Not since cycle 14 peaked in February 1906 has there been a solar cycle with fewer sunspots. We are currently more than six years into Solar Cycle 24 and the current nearly blank sun may signal the end of the solar maximum phase. If history is a guide, it is safe to say that weak solar activity for a prolonged period of time can have a cooling impact on global temperatures in the troposphere which is the bottom-most layer of Earth’s atmosphere – and where we all live. There have been two notable historical periods with decades-long episodes of low solar activity. The first period is known as the “Maunder Minimum,” named after the solar astronomer Edward Maunder, and it lasted from around 1645 to 1715. The second one is referred to as the “Dalton Minimum,” named for the English meteorologist John Dalton, and it lasted from about 1790 to 1830. Both of these historical periods coincided with colder-than-normal global temperatures in an era now referred to by many scientists as the “Little Ice Age”.

The increasingly likely outcome for another historically weak solar cycle continues the recent downward trend in sunspot cycle strength that began over twenty years ago during solar cycle 22. If this trend continues for the next couple of cycles, then there would likely be increasing talk of another “grand minimum” for the sun which is an extended period of low solar activity. Some solar scientists are already predicting that the next solar cycle, #25, will be even weaker than this current one. However, it is just too early for high confidence in those predictions since many solar scientists believe that the best predictor of future solar cycle strength involves activity at the sun’s poles during a solar minimum and the next solar minimum is still likely several years away.

Aarhus University, Denmark: The activity of the Sun is an important factor in the complex interaction that controls our climate. New research now shows that the impact of the Sun is not constant over time, but has greater significance when the Earth is cooler. Since the end of the Last Ice Age about 12,000 years ago, the Earth has generally experienced a warm climate. However, the climate has not been stable during this period, when temperatures have varied for long periods. We have generally had a slightly cooler climate during the last 4,000 years, and the ocean currents in the North Atlantic have been weaker.

Abstract from Geology (Journal of the Geological Society of America): Mounting evidence from proxy records suggests that variations in solar activity have played a significant role in triggering past climate changes. However, the mechanisms for sun-climate links remain a topic of debate. Here we present a high-resolution summer sea-surface temperature (SST) record covering the past 9300 yr from a site located at the present-day boundary between polar and Atlantic surface-water masses. The record is age constrained via the identification of 15 independently dated tephra markers from terrestrial archives, circumventing marine reservoir age variability problems. Our results indicate a close link between solar activity and SSTs in the northern North Atlantic during the past 4000 years; they suggest that the climate system in this area is more susceptible to the influence of solar variations during cool periods with less vigorous ocean circulation. Furthermore, the high-resolution SST record indicates that climate in the North Atlantic regions follows solar activity variations on multidecadal to centennial time scales.

This news is devastating to the Church of Global Warming and policy promulgated by the U.N. and the Obama administration. It will be interesting to see if the lap-dog media attempt to discredit the observational data.

400 yrs sunspots

See also:

Climate change in perspective

Evidence that CO2 emissions do not intensify the greenhouse effect

Some basic facts on carbon dioxide and climate


The Stadium Wave Hypothesis – how the climate cycles between warm and cool

All climate models used by the IPCC failed to predict the “pause” in global warming since 1998. Two Georgia Tech researchers, Dr. Marcia Glaze Wyatt and Dr. Judith A. Curry, hypothesize that multi-decadal oscillations in atmospheric and oceanic circulation regimes, such as the Atlantic Multidecadal Oscillation (AMO) and the Pacific Decadal Oscillation (PDO) can amplify or diminish longer term atmospheric warming or cooling.

Their hypothesis is likened to a “stadium-wave signal that propagates like the cheer at sporting events whereby sections of sports fans seated in a stadium stand and sit as a ‘wave’ propagates through the audience.  In like manner, the ‘stadium wave’ climate signal propagates across the Northern Hemisphere through a network of ocean, ice, and atmospheric circulation regimes that self-organize into a collective tempo.”

This study analyzed data from the atmosphere, ocean, and sea ice since 1900.  “The study provides an explanation for seemingly incongruous climate trends, such as how sea ice can continue to decline during this period of stalled warming, and when the sea ice decline might reverse.  After temperatures peaked in the late 1990s, hemispheric surface temperatures began to decrease, while the high latitudes of the North Atlantic Ocean continued to warm and Arctic sea ice extent continued to decline. According to the ‘stadium wave’ hypothesis, these trends mark a transition period whereby the future decades will see the North Atlantic Ocean begin to cool and sea ice in the Eurasian Arctic region begin to rebound.”

The Stadium Wave hypothesis predicts that the current “pause” in warming will continue well into the 2030s.

Near the end of their paper, the researchers provide this caveat: “While evidence strongly supports our hypothesis of a secularly varying climate signal propagating through a hemispheric network of synchronized ocean, atmosphere, and ice indices during the 20th century, we cannot know if this variability, tempo, and sequential chronology will continue into the future. How changes in external forcing might affect the Eurasian Arctic sea ice in context of an apparent quasi-oscillatory ocean-ice-atmosphere system is a burning question.”

They do note that study of 300 year proxy data suggests changes in tempo and amplitude of the “Stadium Wave” did occur prior to the 1800s.

The bottom line is that this hypothesis explains the behavior of global temperature while the carbon dioxide hypothesis does not.

The research is published in the September issue of Climate Dynamics.

See more detail at Dr. Judith Curry’s blog here. You can download the full manuscript (in pre-publication form) here.

Another paper relating the AMO and PDO cycles to conditions in the Southwestern US concludes: “If the AMO continues its quasi-cyclic behavior the US SW temperature should remain stable and the precipitation should significantly increase during the next few decades.”  That bodes well for our future water supply.  For that story see here.

See also:

The significance of the 17-year pause in global warming

Critique of the IPCC’s Summary for Policymakers

IPCC downplays abrupt climate change danger

Why climate science is fallible

IPCC AR5 climate report may be dead on arrival

IPCC 95% Certain – hold on to your wallets

The new IPCC climate report is already in trouble

More evidence that climate models are wrong