1, When do scientists expect the next glacial to start, assuming no anthropogeni

Question

1,

When do scientists expect the next glacial to start, assuming no anthropogenic CO2 emissions?

In the next 10,000 years

In 100,000 years

Never

Any day now

In ~30,000 years

2.  

Why is the length of the current interglacial longer than the past two interglacials?

Eccentricity is very low

Less volcanic eruptions

Precession is low

3.  

Which of the following time-scales of change in Earth's orbit does not appear to have major implications for climate change during the Pleistocene Epoch?

5600 years

26,000 years

41,000 years

100,000 years

400,000 years

4.  

The Holocene climate maximum was

warmer than today due to higher levels of greenhouse gases

warmer than today due to plate tectonics

colder than today due to changes in Earth's orbital configuration

warmer than today during the summer at high latitudes due to changes in Earth's obliquity

5.

We can delay the start of the next glacial if we keep releasing greenhouse gases into the atmosphere.

6.  

The climate in the Holocene is relatively unstable compared to the last glacial because of lesser ice sheet extent.

Question 18 options:

In the next 10,000 years

In 100,000 years

Never

Any day now

In ~30,000 years

Explanation / Answer

1)

Running simulations with an Earth System model, the researchers find that if atmospheric CO2 were still at pre-industrial levels, our current warm “interglacial” period would tip over into a new ice age in around 50,000 years’ time.

But CO2 emissions from human activity in the past, and those expected in the future, mean the next ice is likely to be delayed to 100,000 years’ time, the researchers say.

This study further confirms what we’ve suspected for some time, that the CO2 humans have added to the atmosphere will alter the climate of the planet for tens to hundreds of thousands of years.

2) A .eccentricity changes, The interglacials, and glacials coincide with cyclic changes in the Earth's orbit. Three orbital variations contribute to interglacials. The first is a change in the Earth's orbit around the sun or eccentricity. The second is a shift in the tilt of the Earth's axis, the obliquity. The third is precession or wobbling motion of Earth's axis.[1] Warm summers in the Southern hemisphere occur when that hemisphere is tilted toward the sun and the Earth is nearest the sun in its elliptical orbit. Cool summers occur when the Earth is farthest from the sun during that season. These effects are more pronounced when the eccentricity of the orbit is large. When the obliquity is large, seasonal changes are more extreme.

3)  Changes in the Earth's orbit brought about by astronomical variations have a strong impact on Earth’s climate. The main cyclicity in the paleoclimatic record is close to 100,000 years, but there is no significant orbitally induced changes in the radiative forcing of the Earth in this frequency range For the past 150 years, humans have been performing an unprecedented experiment on Earth's climate. Human activities, mainly fossil fuel combustion, are increasing concentrations of greenhouse gases (GHGs) in the atmosphere. These gases are trapping infrared radiation emitted from the planet's surface and warming the Earth. Global average surface temperatures have risen about 0.7°C (1.4°F) since the early 20th century. Earth's climate is a complex system that is constantly changing, but the planet is warmer today than it has been for thousands of years, and current atmospheric carbon dioxide (CO2) levels have not been equaled for millions of years. As we will see below, ancient climate records offer some clues about how a warming world may behave. They show that climate shifts may not be slow and steady; rather, temperatures may change by many degrees within a few decades, with drastic impacts on plant and animal life and natural systems. And if CO2 levels continue to rise at projected rates, history suggests that the world will become drastically hotter than it is today, possibly hot enough to melt much of Earth's existing ice cover. Figure 1 depicts projected surface temperature changes through 2060 as estimated by NASA's Global Climate Model.

4) C, As on Earth, Mars’ orbital elements (obliquity, eccentricity, argument of perihelion) exhibit oscillations known as Milankovitch cycles at periods varying from 50,000 to several million yearsThe obliquity and eccentricity oscillations are much larger in amplitude on Mars than on Earth (Fig. 8). Milankovitch cycles cause climate variations in two ways. First, they control the distribution of incoming solar radiation (insolation) on both an annual average and seasonal basis as functions of latitude. Second, because Milankovitch cycle variations of insolation force variations of annual average surface temperature, they can drive exchanges of volatiles between various surface reservoirs and between surface reservoirs and the atmosphere.

5) true,CO2 emissions from human activity in the past, and those expected in the future, mean the next ice is likely to be delayed to 100,000 years’ time, the researchers say.

6), true, During ice-age glacial maxima of the last ?2.6 million years, ice sheets covered large portions of the Northern Hemisphere. Records from the retreat of these ice sheets during deglaciations provide important insights into how ice sheets behave under a warming climate. During the last two deglaciations, the southernmost margins of land-based Northern Hemisphere ice sheets responded nearly instantaneously to warming caused by increased summertime solar energy reaching the Earth. Land-based ice sheets subsequently retreated at a rate commensurate with deglacial climate warming. Past ice sheets have retreated rapidly, raising global sea level at rates >1 cm per year, with marine ice sheets collapsing and terrestrial ice sheets retreating in a more gradual fashion.

Climate change in the Baltic Sea basin during the Holocene has been the result of various external and internal factors: changes in incoming seasonal solar radiation due to slow changes in the Earth’s orbit, variations in the concentration of stratospheric aerosol caused by volcanic activity , change in the greenhouse gas content of the atmosphere due to natural factors, change in surface albedo of the sea-lake itself and in the surrounding land vegetation, and change in the intensity and type of circulation due to changes in basin salinity.

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