What defence do we have against politically-motivated scientists?

[KrazyHorse]

Ned, you're obviously trying a shotgun approach here. Come up with well-founded arguments or stop wasting my time.

[Ned]

OK, what I think is that the amount of sun reaching open or vegitated ground is the most significant factor in ice age/warm periods. As our orbit and spin axis changes, the total amount of sun reaching open ground varies as the world's land masses are distributed in such a way that the bulk of he land is in the North. You could probably actually trace the Mini Ice Age to variations in our orbit and spin axis -- with some lag that might depend on whether we are entering or leaving a cold period.

I think it is also clear that given historical data temperature data vs. spin axis and orbit, we could actually compute expected global temperatures based upon our current orbit and spin axis. Then we could compare this data with the actual temperature data we see in modern times to compute the variance between the two to see just how much man is actually affecting temperatures.

[Ned]

But, what this exercise might also show is that we are only differing the next ice age. That information might critically inform policy.

[KrazyHorse]

Originally posted by Ned
OK, what I think is that the amount of sun reaching open or vegitated ground is the most significant factor in ice age/warm periods

Yet another of Ned's wild-ass hypotheses with no basis in observation or theory.

[KrazyHorse]

What I think is that Puff the magic dragon comes every 100000 years and bathes the earth in his magical flames. When he does so the temperature rises. Then, all the forests burn and the CO2 rises. Then Puff goes away for a bit and the cycle repeats itself.

Ergo global warming doesn't exist and we should invest heavily in anti-flying reptile defences.

[Ned]

Originally posted by KrazyHorse


Yet another of Ned's wild-ass hypotheses with no basis in observation or theory.

KH, Apology?


"In the past million years, the Earth experienced a major ice age about every 100,000 years. Scientists have several theories to explain this glacial cycle, but new research suggests the primary driving force is all in how the planet leans.

The Earth’s rotation axis is not perpendicular to the plane in which it orbits the Sun. It's offset by 23.5 degrees. This tilt, or obliquity, explains why we have seasons and why places above the Arctic Circle have 24-hour darkness in winter and constant sunlight in the summer.

But the angle is not constant – it is currently decreasing from a maximum of 24 degrees towards a minimum of 22.5 degrees. This variation goes in a 40,000-year cycle.

Peter Huybers of Woods Hole Oceanographic Institution and Carl Wunsch of the Massachusetts Institute of Technology have compared the timing of the tilt variations with that of the last seven ice ages. They found that the ends of those periods – called glacial terminations – corresponded to times of greatest tilt.

"The apparent reason for this is that the annual average sunlight in the higher latitudes is greater when the tilt is at maximum," Huybers told LiveScience in a telephone interview."

....

"The last major glacial thaw was 10,000 years ago, which means that the Earth is scheduled to head into another ice age. Whether human influences could reverse this, Huybers was hesitant to speculate."

http://www.livescience.com/forcesofnature/050330_earth_tilt.html

[Ned]

Also, this appears to be the coup-de-gras:

"Scientists have long studied how variations in Earth's orbit relate to ice ages, cycles of glacier building and retreat, and even mass extinctions. New research has uncovered some surprising relationships among all these things.

About 23 million years ago, a huge ice sheet spread over Antarctica, temporarily reversing a general trend of global warming, decreasing ice volume and ushering in a generally calm climatic period. The new study suggests this period corresponded with a rare combination of events in the pattern of Earth's trek around the Sun.

The idea that cyclical variations in Earth's orbit can cause major climate changes was first proposed by astrophysicist Milutin Milankovitch. The main variables are eccentricity, obliquity and precession.

Eccentricity refers to the changing shape of Earth's orbit around the Sun, which varies from nearly circular to elliptical over a cycle of about 100,000 years. Obliquity refers to the angle at which Earth's axis is tilted with respect to the plane of its orbit, varying between 22.1 degrees and 24.5 degrees over a 41,000-year cycle. Precession is the gradual change in the direction Earth's axis is pointing, a 21,000-year cycle during which the axis carves out an imaginary cone shape.

"What we found at 23 million years ago is a rare congruence of a low point in Earth's eccentricity and a period of minimal variation in obliquity," said James Zachos, a professor of Earth sciences at the University of California, Santa Cruz.

The result was a period of about 200,000 years when there was unusually low variability in the planet's climate, with reduced extremes of seasonal warmth and coldness, say Zachos and his colleagues.

Earth's orbit was nearly circular, so its distance from the Sun stayed about the same throughout the year. In addition, the tilt of Earth's axis, which gives rise to the seasons, varied less than usual. In other words, the tilt doesn't always vary between the same extremes in its 41,000-year cycles; the obliquity cycle itself varies in amplitude over a longer period of about 1.25 million years. Similarly, the eccentricity cycle peaks every 400,000 years.

When the researchers began the study, "we never suspected that the transient glaciation at 23 million years ago had anything to do with orbital anomalies," Zachos said.

Zachos worked with Nicholas Shackleton and Heiko Pälike of Cambridge University, Justin Revenaugh of UC Santa Cruz, and Benjamin Flower of the University of South Florida. Their findings are discussed in the April 13 issue of the journal Science.

The researchers obtained detailed climate records by analyzing sediment cores drilled out of the ocean floor. Cutting through layers of sediments laid down over millions of years, such cores contain a chronological record of past climates written in the chemistry of fossilized shells left behind by tiny marine organisms.

"I'm not sure everyone will be convinced that the orbital anomaly alone is responsible," Zachos said. "But the congruence of those orbital cycles is a very rare event, and the fact that it exactly corresponds with this rare climatic event is compelling."

http://www.space.com/scienceastronomy/planetearth/orbit_climate_010212.html

[Ned]

"Evidence from power spectra of deep-sea oxygen isotope time series suggests that the climate system of Earth responds nonlinearly to astronomical forcing by frequency modulating eccentricity-related variations in insolation. With the help of a simple model, it is shown that frequency modulation of the approximate 100,000-year eccentricity cycles by the 413,000-year component accounts for the variable duration of the ice ages, the multiple-peak character of the time series spectra, and the notorious absence of significant spectral amplitude at the 413,000-year period. The observed spectra are consistent with the classic Milankovitch theories of insolation, so that climate forcing by 100,000-year variations in orbital inclination that cause periodic dust accretion appear unnecessary. "

http://www.sciencemag.org/cgi/content/short/285/5427/564

[Drogue]

Originally posted by SpencerH
It's absurd to analyse a countries CO2 pollution in relation to population (in the context of Kyoto).

How so? Should the UK be allowed to pollute as much, in total, as the US? Should we just set a cap on total pollution that everyone must stay below? Country boundaries are arbitrary lines. What matters is how much each person is polluting. It makes sense to have a limit based on the amount of people in your country. Else countries could just break up. Like if the US decided it was going to be 50 individual states rather than one country, no state would be the world's biggest polluter. However there's no overall change in pollution output, and no change in per capita output.

I do agree with Ned's point, there should be the same rules for all countries. Like a limit per capita or somesuch. It's just the developing world pollute a lot, lot less than the developed world.

[Ned]

"Mechanisms responsible for the initiation of major glaciation in the Northern Hemisphere at about 2.75 million years ago are poorly understood. A laminated terrestrial sequence from Pula maar, Hungary, containing about 320,000 years in annual layers between 3.05 and 2.60 million years ago, provides a detailed record of rates of climatic change across this dramatic transition. An analysis of the record implies that climatic variations at sub-Milankovitch frequencies (less than or equal to 15,000 years) were an important driving force during this transitional interval and that, as the threshold was approached, these increased in frequency and amplitude, possibly providing the final trigger for the amplification of Northern Hemisphere ice sheets."

http://www.sciencemag.org/cgi/content/short/285/5427/568

[Ned]

Originally posted by Drogue

How so? Should the UK be allowed to pollute as much, in total, as the US? Should we just set a cap on total pollution that everyone must stay below? Country boundaries are arbitrary lines. What matters is how much each person is polluting. It makes sense to have a limit based on the amount of people in your country. Else countries could just break up. Like if the US decided it was going to be 50 individual states rather than one country, no state would be the world's biggest polluter. However there's no overall change in pollution output, and no change in per capita output.

I do agree with Ned's point, there should be the same rules for all countries. Like a limit per capita or somesuch. It's just the developing world pollute a lot, lot less than the developed world.

More to the point, the scheme should actually be effective to do something about greenhouse gases. Simply capping everyone at a per-capita level is designed to fail in this regard as poluting industries flow out of high per capita areas into low per capita areas.

And the answer is NOT global socialism that would prevent this.

But I would also suggest people review data I just posted on the causes of ice ages. We might actually need greenhouse gases to forestall the ice age that is now due.

[SpencerH]

Originally posted by KrazyHorse

we should invest heavily in anti-flying reptile defences.

Amen to that, so long as it also works against other giant reptiles (such as Godzilla).

It's interesting that you seem to have faith in the ice-core CO2 readings when there are known artifacts, possible unrecognized artifacts, and discrepancy with other estimates of atmospheric CO2 (ie it's typical science).

To me, the assumption by the 'chicken little types' that the core samples are completely accurate is typical scientific hubris bolstered by the media and scare-monger politicians (like Gore).

Should we reduce pollution? Of course we should. It's pathetic that more hasn't been done.
Should we beggar the world economy based on this data? No.

[Drogue]

Originally posted by Ned
More to the point, the scheme should actually be effective to do something about greenhouse gases. Simply capping everyone at a per-capita level is designed to fail in this regard as poluting industries flow out of high per capita areas into low per capita areas.

That's the whole point. It has two effects - it lowers the level of overall pollution (thus reducing any greenhouse effects) and spreads the pollution out evenly so that the local effects of pollution are lessened. As long as the limit is set sensibly, it'll reduce it by the right amount.

Or you could do it the market way and have global tradable permits. These do have serious issues, but they'd work better than flat caps.

It seems if we can agree on the purposes - reducing greenhouse gases in the most efficient way - and look towards scientists and economists to look at damage and cost of pollution reduction so as to estimate what level of pollution is efficient, then we just need to come up with the most efficient way of hitting that target. If we only care about the global effect, that is of total pollution, we should be able to have a decent tradeable permit system in effect, as the issues with these are usually that in local settings there isn't a competitive market for them, as only a few polluters actually pollute in any small area.

[Ned]

"Here's a story to cool you off on a hot summer day. One of the major mysteries of ice ages may have been solved by a Harvard climatologist.

Most scholars believe that much of North America, Europe and northern Asia were buried under thousands of feet of ice when Earth was furthest away from the sun during the northern hemisphere summer. Our planet completes an oval or elliptical orbit around the sun once a year. Presently, we swing away from our natural heater during the north's summer, and approach it in winter. Ten thousand years ago, the situation was reversed. Earth moved closest to the sun during summer in the northern hemisphere and moved away in winter. This happened because Earth's axis, on which it rotates once every 24 hours, wobbles like a gigantic top. Scientists call this wobbling "precession."

Our spin axis not only wobbles, it tilts at an angle of about 23.5 degrees from the vertical. While the 24-hour rotation brings us days and nights, the tilt gives us four seasons. In the winter, the northern hemisphere tilts away from the sun, providing less radiation than in the summer when the axis tilts the other way.

"Typically, people believe that ice ages ended when Earth began to orbit closer to the sun during northern hemisphere summers," explains Peter Huybers, an environmental fellow in the Department of Earth and Planetary Sciences at Harvard. "At such times, the intensity of solar radiation that reaches our atmosphere increases. This increase is thought to enhance melting, eventually ending an ice age."

It's a neat story, but Huybers doesn't buy it. When Earth is closest to the sun, it travels faster than when it's farther away, a fact discovered by the German astronomer Johannes Kepler in the 1600s. This increased speed counterbalances the more intense sunshine because it makes the summer melting period shorter. As a result, Huybers says, "precession appears to exert little effect on the melting of ice sheets."

What does pace the buildup and collapse of ice sheets is changes in the tilt of the Earth's axis, the imaginary line that runs through the north and south poles. Increasing the planet's tilt increases the intensity of summer sun without making summer shorter. That increases melting. Therefore, ice ages come and go mostly because of changes in the tilt of Earth's orbit around the sun. It's this so-called obliquity, not the wobble of the planet, that is responsible for the dramatic shifts in Earth's ice cover. "

....

"To further support his theory, Huybers did another test. He used temperature records from across North America to calculate the potential for melting ice. "When sunlight is considered over the whole of summer, it is a much better predictor of potential melting than any previous approaches used to calculate how much melting goes on," he explains. "There turns out to be an excellent correlation between this potential melting and the amount of ice known to cover Earth during the last ice ages, two to one million years ago." Huybers published his calculation and ideas in the June 23 edition of Science, the journal of the American Association for the Advancement of Science. "

http://www.news.harvard.edu/gazette/2006/07.20/26-iceage.html

[Jon Miller]

Originally posted by Drogue

How so? Should the UK be allowed to pollute as much, in total, as the US? Should we just set a cap on total pollution that everyone must stay below? Country boundaries are arbitrary lines. What matters is how much each person is polluting. It makes sense to have a limit based on the amount of people in your country. Else countries could just break up. Like if the US decided it was going to be 50 individual states rather than one country, no state would be the world's biggest polluter. However there's no overall change in pollution output, and no change in per capita output.

I do agree with Ned's point, there should be the same rules for all countries. Like a limit per capita or somesuch. It's just the developing world pollute a lot, lot less than the developed world.

Physical size plays a factor also, not just population.

Some of us like space.

JM