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Assuming the axial tilt of the Earth was increased to roughly 30°, and the orbital eccentricity roughly doubled(0.03 as opposed to 0.016) so that the average temperature stayed the same, but the summers became hotter, the winters colder and the seasonal changes from latitude became more extreme, what kind of weather differences could be expected?

I'm building a world that is very Earthlike other than the changes mentioned above and I'm having trouble figuring out how it would affect the weather on the planet. I know that the seasonal extremes would cause more severe storms, maybe even the theoretical hypercanes, but I am not very well versed in meteorology, let alone climate models for an entire planet.

I've seen plenty of questions about the planet having no axial tilt, but mot a ton about a slightly higher tilt.

I did find several Quora answers that are almost exactly what I was asking: https://www.quora.com/If-the-Earths-axial-tilt-increased-to-30-degrees-what-effects-would-it-have-on-Earths-climate-zones

The only problem is that there is almost no talk of how weather would be affected, as most of the answers are about how it would affect Earth.

All I'm really looking for is the expected changes to the yearly weather. Would there be increased rainfall in the summer? Why's that? Would the northern winters be non-stop blizzards? No? Alright. Just a basic rundown.

Any help or advice on where to start looking would be appreciated.

P.S. I understand that weather is an incredibly unpredictable and complicated subject, and that I'm making a highly theoretical model here, so perhaps just some guesses based on the fact that summers are warmer, winters are colder and the poles experience more intense variations.

Thanks!

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    $\begingroup$ Note in an eccentric orbit a planet will be moving fastest at perihelion (closest point to the sun) and slowest at aphelion (furthest point) so on average it will spend more time further from the sun than you would expect by doubling the eccentricity. Also note that the southern hemisphere suffers more extreme climatic variation than the northern hemisphere in part because perihelion occurs during the southern summer and aphelion during the southern winter. $\endgroup$
    – Slarty
    May 11, 2020 at 17:23
  • $\begingroup$ Very good points, so the planet will likely be cooler than Earth, and the southern hemisphere will likely see a hotter and dryer climate. Thanks for the info! $\endgroup$
    – Jack Foisy
    May 11, 2020 at 17:37
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    $\begingroup$ The main problem with this question is that it is not well defined. Indeed, "how weather would be affected" is meaningless. How will it be affected where? Southern England? Northern Kazakhstan? Nizhny Novgorod? Melbourne? How it will be affected when? The climate and the biosphere are interdependent; since Earth presumably has had this 30° axial tilt since the beginning of life, it follows that natural evolution would have taken a different path. Moreover, the system is known to be chaotic. There is no such thing as long-term stability in Earth's climate. $\endgroup$
    – AlexP
    May 11, 2020 at 19:01
  • $\begingroup$ I'll try to clarify better and make the question more brief, but it's really a question of change in the climate zones and general weather that may be expected. Like if the tropics would be wetter or if the poles would get colder $\endgroup$
    – Jack Foisy
    May 12, 2020 at 0:19
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    $\begingroup$ There would be LOTS of wind, assuming that seasons would be opposite in different hemispheres. Extreme heat on one side, and extreme cold on the other, where the atmospheres combine, it would cause continual wind through the globe. It is also possible that glaicers would melt during summers. $\endgroup$
    – bean delivery man
    Sep 6, 2020 at 14:59

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Warmer overall, no polar ice caps, with extreme seasons at high latitudes; possibly wetter as well

Essentially, this hypothetical is an extreme case of the Milankovitch cycles in real life, which drive Earth's ice ages (glacials/interglacials).

There is a ~100,000 year cycle of varying orbital eccentricity and a ~40,000 year cycle of varying axial tilt.

(NASA page: https://climate.nasa.gov/news/2948/milankovitch-orbital-cycles-and-their-role-in-earths-climate/)

Actually, 0.03 eccentricity is well within the range of the RL Earth over geologic time, though higher than the current value; according to the linked NASA page, it varies from 0.0034 to 0.058.

The real game-changer here is the 30-degree tilt (vs. 22.1 to 24.5 in reality).

Per the linked page, "Larger tilt angles favor periods of deglaciation (the melting and retreat of glaciers and ice sheets). These effects aren’t uniform globally -- higher latitudes receive a larger change in total solar radiation than areas closer to the equator."

So with this very large tilt angle, Earth probably loses all glaciation (due to warmer polar summers). Ice is very reflective, so this Earth will receive more solar energy, and be somewhat warmer overall. All that water from the polar caps will be "available" in the water cycle as well - so sea levels will be much higher, and it may be rainier.

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  • $\begingroup$ I totally forgot that I asked this question, but this is a good answer. Thank you! $\endgroup$
    – Jack Foisy
    Mar 23 at 21:19
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Cooler than Earth yes, but the Southern hemisphere would tend to experience very warm summers and very cold winters to an even greater extent than our southern hemisphere already experiences.

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