The Climate, Environment and Energy Thread

[DJC]

My issue with the whole climate change debate is that it disregards the following:

At least five major ice ages have occurred throughout Earth's history: the earliest was over 2 billion years ago, and the most recent one began approximately 3 million years ago and continues today (yes, we live in an ice age!). Currently, we are in a warm interglacial that began about 11,000 years ago.

https://www.ncdc.noaa.gov/abrupt-climate...l%20Cycles

I have no issues with us attempting to be greener as we have caused more damage to the overall environment than any other species (I doubt you will find any other species that logs, or pollutes to the same levels as humanity) but the answer to these problems is quite simple.

Humanity is a parasite on the earth, and appears hell bent on consuming it, and until we work out that exponential growth of humanity correlates with the exponential growth of pollutants which means that the only real way forward is to live simpler and consume less, and perhaps grow slower and maybe revert back to dying younger.  Remember when living past 70 was the exception not the norm?  Now the exception is the opposite, and 70 year olds run countries.

The science of climate change is enmeshed within the study past climatic fluctuations Thry.  What that tells us is that the climate is changing faster now than at any time in the past. 

And we’re not in an ice age now: Glacial = ice age, Interglacial = no ice age.

The geological time scale used Holocene to denote the current geological age.  It’s now called the Anthropocene to reflect the period during which human activity has been the dominant influence on climate and the environment.  The Holocene commenced at the end of the last ice age (or glacial period) about 10,000 years ago.  The Anthropocene’s commencement is being pushed back to around 15,000 years as it is argued that human impact on the environment and climate commenced during the last ice age.

Palynological studies suggest that Aboriginal burning practices changed the Australian environment and biodiversity tens of thousands of years before that.

The elephant in the room is the exponential growth of the human population as well as the mantra that economies must continue to grow.  We can reduce consumption and waste and minimise environmental impacts but we’ll continue on a path to oblivion as long as humanity continues to breed like rabbits.

[LP]

Interestingly, the population growth is now expected to plateau between 2050 to 2100, so in this regard it won't be growing exponentially like it has in the past. I think Attenborough covered this in his recent A Life on Our planet documentary.

Apparently this is now validated across several disciplines including epidemiology, macro-economics, ecology and sociology. The influences are complex, related to changes in society, female empowerment, education, wealth and health. It seems the longer we are likely to live, the greater the chances of survival in a healthy state, the less children we have on average.

When I first heard this a few years back I thought it might be a bit of propaganda, designed to diminish the need for urgent change, but it isn't it and it doesn't diminish the need to act at all.  Change is still required, because despite population growth slowing, resources continue to diminish and energy consumption per-capita rises. This is where the scope of the climate change issue broadens to become much much more than just greenhouse gas, and is the is the spawn of continuous economic growth which is different to population growth.

The ultimate climate change buster is fusion energy, it makes all other sources of energy redundant and filthy by comparison, but there is no guarantee it is either possible or cheap. Pretty much every other source of energy, is dirty by comparison, even solar, wind and tidal. But even if fusion became globally available tomorrow, resources would still diminish.

Humans are not a good judge of these things, for example almost every person you ask will tell you hydroelectric is clean. When in fact it's one of the most environmentally damaging forms of energy production you can have. They think nuclear fission is dirty and dangerous, when it's one of the safest and environmentally clean sources of energy currently available. Humans judge these things on emotion, to a human a nuclear power plant is a giant atomic bomb while a hydroelectric dam is a beautiful eco friendly lake, nothing is further from the truth. We see the very rare instantaneous effects of a major event, and ignore numerous occurences of the creeping death!

[Thryleon]

The science of climate change is enmeshed within the study past climatic fluctuations Thry.  What that tells us is that the climate is changing faster now than at any time in the past. 

And we’re not in an ice age now: Glacial = ice age, Interglacial = no ice age.

The geological time scale used Holocene to denote the current geological age.  It’s now called the Anthropocene to reflect the period during which human activity has been the dominant influence on climate and the environment.  The Holocene commenced at the end of the last ice age (or glacial period) about 10,000 years ago.  The Anthropocene’s commencement is being pushed back to around 15,000 years as it is argued that human impact on the environment and climate commenced during the last ice age.

Palynological studies suggest that Aboriginal burning practices changed the Australian environment and biodiversity tens of thousands of years before that.

The elephant in the room is the exponential growth of the human population as well as the mantra that economies must continue to grow.  We can reduce consumption and waste and minimise environmental impacts but we’ll continue on a path to oblivion as long as humanity continues to breed like rabbits.

I only disagree with one part of your post DJC, and that is that the evidence points to us still being in an Ice Age even though you might have stated we arent because even at a recent trivia night I attended the correct answer was that we are technically still in one, (my gut said that its true was a better trivia answer so we got the points on that one).


https://www.amnh.org/explore/ology/earth...ce-age-end

Ive read this up a few times, because I used to have a theory that we were on track with respect to natural cycles and the earth warming because I was sick of the climate debate, and the answers I found were to debunk that theory and keep reading and understand that we are actually having a bigger impact, and that has been thus far to stave off the next glacial period thanks to 100 years of warming which will either result in an over correction and flip to a massive ice age to fix it, or cause a lot of damage.  Thing is, it seems to point to the earth wobble, and bulge causing more change here than not.

Scientists are still working to understand what causes ice ages. One important factor is the amount of light Earth receives from the Sun. The amount of sunlight that reaches Earth can vary quite a lot, mainly due to three factors:

    how much Earth is tilted relative to the Sun
    whether Earth wobbles a lot or a little as it spins on its axis (kind of like how a toy top can wobble a lot or a little as it spins)
    the shape of Earth's orbit as it goes around the Sun (whether it is shaped more like a circle or more like an ellipse or oval)

https://en.wikipedia.org/wiki/Ice_age

Glacials and interglacials
See also: Glacial period and Interglacial
Shows the pattern of temperature and ice volume changes associated with recent glacials and interglacials
Minimum and maximum glaciation
Minimum (interglacial, black) and maximum (glacial, grey) glaciation of the northern hemisphere
Minimum (interglacial, black) and maximum (glacial, grey) glaciation of the southern hemisphere

Within the current glaciation, more temperate and more severe periods have occurred. The colder periods are called glacial periods, the warmer periods interglacials, such as the Eemian Stage.[1] There is evidence that similar glacial cycles occurred in previous glaciations, including the Andean-Saharan[41] and the late Paleozoic ice house. The glacial cycles of the late Paleozoic ice house are likely responsible for the deposition of cyclothems.[42]

Glacials are characterized by cooler and drier climates over most of the earth and large land and sea ice masses extending outward from the poles. Mountain glaciers in otherwise unglaciated areas extend to lower elevations due to a lower snow line. Sea levels drop due to the removal of large volumes of water above sea level in the icecaps. There is evidence that ocean circulation patterns are disrupted by glaciations. The glacials and interglacials coincide with changes in orbital forcing of climate due to Milankovitch cycles, which are periodic changes in the Earth's orbit and the tilt of the Earth's rotational axis.

The earth has been in an interglacial period known as the Holocene for around 11,700 years,[43] and an article in Nature in 2004 argues that it might be most analogous to a previous interglacial that lasted 28,000 years.[44] Predicted changes in orbital forcing suggest that the next glacial period would begin at least 50,000 years from now. Moreover, anthropogenic forcing from increased greenhouse gases is estimated to potentially outweigh the orbital forcing of the Milankovitch cycles for hundreds of thousand of years.[45][5][4]

The variation of sunlight reaching Earth is one cause of ice ages.

Over thousands of years, the amount of sunshine reaching Earth changes by quite a lot, particularly in the northern latitudes, the area near and around the North Pole. When less sunlight reaches the northern latitudes, temperatures drop and more water freezes into ice, starting an ice age. When more sunlight reaches the northern latitudes, temperatures rise, ice sheets melt, and the ice age ends. But there are many other factors. So if you became a climate scientist one day, you could make your own discoveries!

[capcom]

We're condemned to live on this planet, we will never survive on another, be it this solar system, or anywhere else.  It's an impossible.

The worst threat to humanity is ourselves and listening to any green alternatives hardly helps.

We MUST go nuclear.  The rest are just distractions

 

[LP]

    how much Earth is tilted relative to the Sun
    whether Earth wobbles a lot or a little as it spins on its axis (kind of like how a toy top can wobble a lot or a little as it spins)
    the shape of Earth's orbit as it goes around the Sun (whether it is shaped more like a circle or more like an ellipse or oval)

[member=105]Thryleon[/member]  This bit is a horribly simplistic hash up between what causes the seasons and what influences long term climate change.

The shape of the earths orbit effectively doesn't vary at all on times scales measured in billions of years, it's almost perfectly round less than 3% elliptical. The Sun's changing flux over that time has far more influence than any small orbital variations but even that solar flux variation is trivial on human time scales.

The earth wobbles (Precession) but this has no long term effect as it is cyclic, and the same applies in regards to the tilt. Small timing variations causing correlations between precession and Earth's position in it's elliptical orbit can cause some slight longer term seasonal variations. This is because a conjunctions between the perihelion, aphelion and precession.

The seasons are cyclic because they are caused by the tilt, the Earth is effectively a big spinning gyroscope pointing mostly in the same direction with a slight precession. But Earth's precession takes 26000 years to complete. Interestingly, the main climate effect of precession is modelled to be an evening out of the seasons mid-cycle, not a change in the averages, at some stage in the 26000 cycle summer and winter would be barely distinguishable around the equator. There is no history of glacial or inter-glacial periods tide to precession, even the Maunder Minimum has been ruled out as a precession effect.

A nice debunking argument for the climate change sceptics who try to claim orbital dynamics is the cause, is that the Earth is closest to the sun(About 5,000,000 km closer) when the Northern Hemisphere is in the middle of it's winter.

[DJC]

I only disagree with one part of your post DJC, and that is that the evidence points to us still being in an Ice Age even though you might have stated we arent because even at a recent trivia night I attended the correct answer was that we are technically still in one, (my gut said that its true was a better trivia answer so we got the points on that one).

Your trivia master was wrong Thry 

This is my bread and butter; you can’t understand Australian archaeology without understanding the climatic context.  For example, the sundering of Bass and Torres Straits and the inundation of what is now the continental shelf had profound effects on the first Australians.

Stone artefacts have been found on Mud Islands in Port Phillip Bay.  While it is possible that Aboriginal people could have navigated there, it would have been an extremely risky voyage in the watercraft they had.  However, recent studies have revealed that Port Phillip Bay was dry land between 1,000 and 2,800 years ago and it would have been possible to walk to what would have been prominent dunes on Port Phillip Plain.  The major causes of the drying up of Port Phillip Bay was sand deposits blocking the Heads combined with higher than normal evaporation rates, reflecting a drier climate at that time.  Port Phillip Bay as dry land features in the oral histories of the Kulin people of central Victoria.

Technically, there are no “ice ages”, it is a lay term.  Climate scientists, geologists, archaeologists, palynologists, etc refer to glacial and inter-glacial periods.  As I said previously, glacial equates to ice age and inter-glacial is not an ice age in lay terms.

Looking at it from the perspective of the geological time scale:

The Pleistocene is the most recent period of repeated glaciations. Until recently, glaciations were a feature of the end of the Pliocene Period (the “ice age” was the Plio-Pleistocene) but the beginning of the Pleistocene has been pushed back to 2.58 Ma so that all recent repeated glaciations are within the Pleistocene era.  In other words, the Pleistocene is the “ice age”.

The Holocene refers to the last 11,700 years, that is, the time since the end of the last major glacial epoch, the Pleistocene or "ice age." There have been the small scale climate shifts since the commencement of the Holocene, including the "Little Ice Age" between about 1,200 and 1,700 CE, but that was restricted to the northern hemisphere. The defining feature of the Holocene is the relatively stable climate, as opposed to the widely fluctuation climate swings of the Pleistocene.  Note that the “Little Ice Age” almost overlaps with the period that Port Phillip Bay was dry land so while it was colder in the northern hemisphere, southern Australia was experiencing higher evaporation rates.  That does suggest warmer temperatures but a much larger part of Australia was arid during the Pleistocene as more of the water budget was locked up in ice caps and glaciers.

Where confusion can arise is the grouping together of the Pleistocene and Holocene as the Quaternary Period.  Most of the 2.59Ma of the Quaternary Period has been glacial so you could say that we are still in a period of repeated glaciation.  Of course, that ignores the fact that Holocene is defined as the period following the repeated glaciation of the Pleistocene.

On top of that is the use of Anthropocene as the most recent geological period.  I don’t think that there is agreement on when human activity became the driver of climate and environmental change but it doesn’t necessarily coincide with the Holocene period.  Many researchers push the commencement of the Anthropocene back beyond 11,700 years BP that is accepted as the end of the Pleistocene.

[LP]

Note that the “Little Ice Age” almost overlaps with the period that Port Phillip Bay was dry land so while it was colder in the northern hemisphere, southern Australia was experiencing higher evaporation rates.  That does suggest warmer temperatures but a much larger part of Australia was arid during the Pleistocene as more of the water budget was locked up in ice caps and glaciers.

Yes, this correlation between ice caps and dry hot periods over low latitudes is frequently overlooked in climate sceptic debates. The general public's assumption is that hot means dry, when history indicates you need more ice at the caps to be dry at low latitudes in the absence of some other effect.

Just An FYI for some readers;
Low Lattiudes are near the equator, +/- 0° north or south, High Latitudes are near the poles, +/- 90° North or South. Be careful when reading about High and Low latitudes, because a term like "Down South" doesn't mean at a Low Latitiude!

[img width=550]https://www.spaceweatherlive.com/images/help/lowmidhigh/EN_World.jpg[/img]

Sometimes I think modern scientists should throw out the historical deference to old terminology, some of the terms used in this case were originally phrased when the debates over the earth being round, flat or hollow were still underway!

[kruddler]

I don't know about what LP posted, but i listened to a podcast on iceages and they agreed with Thry and his trivia master. We are still in the latter stages of an ice age.

I cannot recall the exact definition and where it came from, but if i had an educated guess at it, it would be the fact we still have ice on our caps.

From memory there was 3 stages. ice age, middle bit aka lesser ice age which we are in now and non-ice age. Obviously the technical jargon is not there, but the point remains.

[Thryleon]

I don't know about what LP posted, but i listened to a podcast on iceages and they agreed with Thry and his trivia master. We are still in the latter stages of an ice age.

I cannot recall the exact definition and where it came from, but if i had an educated guess at it, it would be the fact we still have ice on our caps.

From memory there was 3 stages. ice age, middle bit aka lesser ice age which we are in now and non-ice age. Obviously the technical jargon is not there, but the point remains.

That was the rationale too in his explanations.

The technicality was that we have periods where the ice levels increase.

[PaulP]

https://theconversation.com/climate-expl...oon-123675

This aside though, the timing is right for the next ice age to come around soon. For the past two and a half million years, the Earth has experienced regular ice ages, related to slow changes to earth’s orbit around the sun and changes in the earth’s axis of rotation (Milankovitch cycles). We are currently in one of the warm periods (interglacials) between ice ages and the present interglacial should be ending about now. The catch is carbon dioxide.