Geologic records over the past million years indicate cycles in the extent of Earth’s surface covered by ice. These ice age cycles are a result of variations in Earth’s orbital geometry, but it is unclear how these variations will continue in the presence of significant human emissions. In a paper published in the Journal of Advances in Modeling Earth Systems, I develop a simple climate model to demonstrate the potential for human-induced climate change to damp out variations in ice coverage, which suggests that human actions today could have long-lasting impacts into the future.

Long-term patterns in Earth’s climate show glacial cycles that correspond to variations in Earth’s orbital geometry and affect the overall amount of sunlight that the planet receives. Known as “Milankovitch cycles”, these variations are observed in geologic reconstructions of temperature and isotopes to show periodic changes every 23,000, 41,000 and 100,000 years. The first two of these correspond directly to changes in Earth’s tilt (i.e. obliquity) and wobble (i.e. precession), but the longer 100,000 year variations in orbit seem too weak in magnitude to drive the strong climate signals we observe.

One solution to this problem is that the climate system itself amplifies these small changes to create more noticeable periodic signals. These amplification mechanisms could be the large thermal intertia of the oceans, the vast energy required to move giant ice sheets, or long-term cycles in greenhouse gases such as carbon dioxide and methane. Any combination of mechanisms such as these could magnify small changes in sunlight from Milankovitch cycles and create the dominant 100,000 year cycle in ice coverage seen in the geologic record.

Studying this problem has proven to be challenging because of the long time scales involved. Most contemporary climate models are focused on patterns of climate on Earth today and in the near future of a few hundred years from now, but few modelers have focused their attention on the more distant future of climate. In my paper I develop a simple climate model that uses stochastic (i.e. randomly generated) forcing to achieve a state of resonance that displays a 100,000 year cycle in ice coverage. The model is an idealization of the more complicated Earth system and provides a tool for exploring the behavior of climate over these long time scales.

Calculations with this model show that the influence of human emissions into the atmosphere can affect the presence of the ice age cycles, either by damping the magnitude of changes or by ceasing the cycles altogether. The simplified calculations here cannot predict exactly when this should occur, but this study points toward the existence of a threshold beyond which ice age cycles may cease as a result of human emissions.

The future of Earth’s climate is becoming increasingly marked by the presence of human activity. Depending on the course of events over the next few hundred years, we may find that the damping or cessation of ice age cycles is yet another indicator of the dawning of the age of the anthropocene.

July/August Shows

We had a fantastic time at 4th Fest this year, thanks to all of our friends who made the trip up from Altoona and elsewhere! It was great to watch the fireworks with familiar faces.

Jul 4 – Mysterytrain @ Central PA 4th Fest (State College, PA)

Jul 12 – Mysterytrain @ Still Meadows Revue II (Jermyn, PA)

Jul 25 – Mysterytrain @ Argilla Brewing Company (Newark, DE)

Aug 22 – Mysterytrain @ Homegrown Cafe (Newark, DE)

Aug 23 – Mysterytrain @ The Austin Dam Show (Austin, PA)

Aug 31 – Mysterytrain @ Peace of Mind 4 (Elizabethville, PA)

We’re also planning on attending Pinnacle Jam at the Kempton Music Center on August 9th to catch the Dark Star Orchestra. It will be nice to have at least one weekend this summer to break out our full camping gear and relax outside with Camp Mysterytrain.

May/June Shows

Very excited to welcome Wes Fehringer as Mysterytrain’s new bass player! Wes has been a long-time friend of the band, and we’re glad that he decided to hop aboard the train…

May 17 – Mysterytrain @ Mid May Cote (Saylorsburg, PA)

May 24 – Mysterytrain @ Shaw’s Bar (Altoona, PA)

May 31 – Mysterytrain @ Duck Duck Goose Campout (Northumberland, PA)

Jun 1 – Mysterytrain @ Goodtimes Getdown (White Haven, PA)

Jun 13 – Mysterytrain @ Minglewood Saloon (Philadelphia, PA)

Jun 20 & 21 – Mysterytrain @ Cosmic Jam 5 (Millmont, PA)

Jun 28 – Mysterytrain @ “Chicken Stock” (Newark, DE)

Looking forward to the 5th annual Cosmic Jam, once again at Sunsational Family Campground. We’ve got two days of music with lots of our friends playing, plus two nights of Mysterytrain!

I recently submitted an essay titled “The transformative value of liberating Mars” to an essay contest sponsored by the Foundational Questions Institute (FQXi). The contest asks participants to consider the question “How Should Humanity Steer the Future?”, and I suggest that the settlement of Mars, approached the right way, could provide some novel solutions to our global problems.

Comments and ratings from the public are welcome, and I appreciate any and all honest feedback!

http://www.fqxi.org/community/forum/topic/2023

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