Sentences with phrase «by orbital changes»

Even if warming episodes were initiated by orbital changes, the warming itself would cause the release of greenhouse gases from sources including the oceans and melting permafrost.

He argues that the total change in insolation caused by orbital changes is minimal (which is true), and therefore CO2 is the main driver of climate.

The predominance of landmasses in the northern hemisphere causes glaciations to predominate over interglacials by about 9 to 1 with a full cycle every 100, 000 years helped along by the orbital changes of the Milankovitch cycles that affect the pattern of insolation on those shifting cloud masses.

So even though past warm episodes may have been initiated by orbital changes that caused warming and thus caused CO2 to rise, which then led to more warming, we know that the current warm episode is being driven by increasing CO2 due to the burning of fossil fuels and the clearing of forests.

-- Even during glacial and interglacial periods — mainly being caused by orbital changes — CO2 content in atmosphere have followed temperature changes.

Similarly, times with especially intense high - latitude NH summer insolation, determined by orbital changes, are thought to trigger rapid deglaciations, associated climate change and sea level rise.

The data show that the sun's variations have been small over the times we care about, the climate responds to variations in sunshine caused by orbital changes, but these are slow.

These are thought to be driven by the large regional changes in insolation driven by orbital changes.

Not exact matches

The now hyper - arid Sahara desert was characterized by a lush extent of grass and consequently reduced dust emission due to changes in Earth's orbital parameters.

Holman says the changes in the transit times of these planets were enhanced by the fact that one of the planets orbits the star in almost exactly half of the time that it takes the other, as such «orbital resonances» increase their gravitational interaction.

In particular, there was no sign of climate change in Indonesia associated with Earth's orbital precession, a wobble caused by Earth's axis tilt that generates differences in sunlight in a 21,000 - year cycle.

The effect of these small orbital changes was amplified by positive feedbacks, such as changes in greenhouse gas levels.

Scientists knew about the warming effects of greenhouse gases, but proponents of global cooling argued that greenhouse warming would be more than offset by Earth's orbital changes.

In the study, researchers analyzed a series of transient Coupled General Circulation Model simulations forced by changes in greenhouse gases, orbital forcing, meltwater discharge and the ice - sheet history throughout the past 21,000 years.

This may help explain some of the changes that are not explained by the orbital curves in the other thread, especially the initiation of warming and cooling since the GCR effects can be much more powerful (partly forcing as postulated in the paper, but also amplification of the weaker orbital forcing).

Another provocative paper, well worth reading, is by Carl Wunsch and attempts to uage the contribution of orbital variations to climate change:

Led by Lars A. Buchhave, from CfA, the study shows a connection between the orbital period of the planet and its size as it changes from a rocky planet to a gas giant.

While natural global warming during the ice ages was initiated by increased solar radiation caused by cyclic changes to Earth's orbital parameters, there is no evident mechanism for correcting Anthropogenic Global Warming over the next several centuries.

It is believed that the PETM was likely initiated by changes of the orbital parameters of the Earth (eccentricity, obliquity and precession of axis) causing an increase in the intensity and distribution of solar radiation reaching the earth (Sexton et al, 2011).

These orbital variations, which can be calculated from astronomical laws (Berger, 1978), force climate variations by changing the seasonal and latitudinal distribution of solar radiation (Chapter 6).

Students can begin by viewing how the Sun impacts the Earth, and then change the mass of the Sun and Earth separately to see how even small changes can greatly affect orbital patterns.

You can also change the camera view of the table, from dynamic and orbital (which follows the players one by one), and when you want to check your hole cards, they lift up in a satisfying «peel» motion.

The response of that model to volcanic forcings, the last ice age, changes in orbital parameters etc. are all «out - of - sample» tests that are not fixed by adjusting parameters.

As mentioned by Chris Colose in # 6, Earth's orbital tilt in the Eemian brought a lot of sunlight to the Arctic in the summer even our planet's overall solar input was not changed.

The theory suggests that the system is pushed by greenhouse gas changes and warming — as well as solar intensity and Earth orbital eccentricities - past a threshold at which stage the components start to interact chaotically in multiple and changing negative and positive feedbacks — as tremendous energies cascade through powerful subsystems.

Raymo and Paillard have a good story about the 100KYr cycle arising from the modulation of the precessional cycle by the changes in the Earth's orbital eccentricity, coupled with some glacial dynamical effects which «rectify» the high frequency precessional signal.

Although the primary driver of glacial — interglacial cycles lies in the seasonal and latitudinal distribution of incoming solar energy driven by changes in the geometry of the Earth's orbit around the Sun («orbital forcing»), reconstructions and simulations together show that the full magnitude of glacial — interglacial temperature and ice volume changes can not be explained without accounting for changes in atmospheric CO2 content and the associated climate feedbacks.

1966 Emiliani's analysis of deep - sea cores shows the timing of ice ages was set by small orbital shifts, suggesting that the climate system is sensitive to small changes.

The important point here is that a small external forcing (orbital for ice - ages, or GHG plus aerosols & land use changes in the modern context) can be strongly amplified by the positive feedback mechanism (the strongest and quickest is atmospheric water vapor - a strong GHG, and has already been observed to increase.

The resulting increased / decreased ice is amplified by «various feedbacks, including ice - albedo, dust, vegetation and, of course, the carbon cycle which amplify the direct effects of the orbital changes.»

As temperatures warmed slightly due to insolation changes caused by orbital cycles, ice sheets retreated slightly.

[Response: the Milankovitch timescale is long and the forcing barely varies due to orbital changes over 100 years so no, they aren't included (they would be for people modelling the last glacial maximum); solar forcing is modelled by change in total solar irradiance (probably as a total number; not sure if changes at different wavelengths are included)-- William]

It's the same series of an initial forcing (change in insolation due to Milankovitch orbital cycles) being amplified by reinforcing feedbacks (change in albedo, change in temperature and partial pressure regulating both CO2 and H2O), but in reverse from an exit from a glacial period.

Time goes by, and the combination of orbital factors slowly change.

With a different overall climatic state or geography, the system might be considerably less sensitive to orbital forcing (obviously it has been less sensitive; orbital forcing has been going on throughout Earth's history (modulated by tidally - induced changes in Earth's rotation and the moon's orbit)-RRB-.

As these particular events took place at the end of a local warm period caused by orbital forcing (see Box 6.1 and Section 6.5.1), these observations suggest that under gradual climate forcings (e.g., orbital) the climate system can change abruptly.

These orbital forcings determine the pacing of climatic changes, while the large responses appear to be determined by strong feedback processes that amplify the orbital forcing.

Glacial periods during the 100,000 - year cycles have been characterised by a very slow build - up of ice which took thousands of years, the result of ice volume responding to orbital change far more slowly than the ocean temperatures reacted.

The National Research Council of the U.S. National Academy of Sciences has embraced the Milankovitch Cycle model... orbital variations remain the most thoroughly examined mechanism of climatic change on time scales of tens of thousands of years and are by far the clearest c...

Complexity theory suggests that the system is pushed by such things as solar intensity and Earth orbital eccentricities — past a threshold at which stage the components start to interact chaotically in multiple and changing negative and positive feedbacks — as tremendous energies cascade through powerful subsystems.

(Were the Earth a solid crystal ball, conservation of energy would prevent these orbital changes from occurring: the Earth could not spin more slowly and the Moon could not gain potential energy by moving away from the Earth while slowing down.)

Choice 5: Does the fact that life on this planet has survived a billion years of climate change caused by orbital mechanics, asteroids, the evolution of photosynthesis, plate tectonics, the variable star we call the sun, chaos, plagues, and possibly supernovae.

«Changes in the CO2 and CH4 content have played a significant part in the glacial - interglacial climate changes by amplifying, together with the growth and decay of the Northern Hemisphere ice sheets, the relatively weak orbital forcingChanges in the CO2 and CH4 content have played a significant part in the glacial - interglacial climate changes by amplifying, together with the growth and decay of the Northern Hemisphere ice sheets, the relatively weak orbital forcingchanges by amplifying, together with the growth and decay of the Northern Hemisphere ice sheets, the relatively weak orbital forcing»

CO2 acts there as a feedback, with warmer / colder oceans holding less / more CO2, and changing CO2 concentrations along with (lagging) temperature changes induced by (forced by) insolation changes due to orbital mechanics.

But some time around 850,000 years ago, the cycle grew to 100,000 years, and ice sheets reached greater extents than they had in several million years — a change too great to be explained by orbital variation alone.

In the case of the 100 kyr ice age cycles, that forcing is high northern latitude summer insolation driven by predictable changes in Earth's orbital and rotational parameters — aka, Milankovitch theory — which has the intial effect of melting glaciers, thereby reducing albedo at those latitudes.

Changes in global - mean temperature induced by Earth's orbital variations may be used to quantify the climate sensitivity.

The theory suggests that the system is pushed by greenhouse gas changes and warming — as well as solar intensity and Earth orbital dynamics — past a threshold at which stage the components start to interact chaotically in multiple and changing negative and positive feedbacks — as tremendous energies cascade through powerful subsystems.

The system is pushed by changes in greenhouse gases, solar intensity or orbital eccentricity.

Reviewed geological data indicate that the history of Arctic sea ice is closely linked with climate changes driven primarily by greenhouse and orbital forcings and associated feedbacks.