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Comment by MichaelApproved | Hacker News Reader

I don't see why these pictures are all terrifying. I'm amazed and impressed by many of them.

The Amazon deforestation one and the Glacier retreat are pretty shocking and terrifying for me. Wish a scale was provided for the deforestation one though, since it's difficult to grasp the scope of its effects without one.

That being said I found the Dubai and Las Vegas ones fascinating.

Watch the Vegas time-lapse again, but look at Lake Mead, not Las Vegas.

EDIT: As for the scale of the Amazon deforestation, by zooming and scrolling the time-lapse map at the bottom of the article, I watched what looks like very nearly the entire Brazilian state of Rondônia go from rainforest to grassland in the 30-ish year period depicted. (Wikipedia says that 70k km² of its 200k km² of rainforest was cleared by 2003, while the map goes to to 2012.) [1]

[1] https://en.wikipedia.org/wiki/Rond%C3%B4nia

I noticed that as well when I watched the Vegas timelapse. I wish there was an overlaying scale showing how much of the water receded, it looked like a significant amount.

Ah great point. This will be really interesting to observe the changes in the water level over the next few years, since Las Vegas is now very efficient with its water usage and has some pretty hard limits on water usage, if I remember correctly.

You don't even need to zoom in that far to see it.

Focus on Brazil and hit play, and you'll see the lower margin of the Amazon just dissolve upwards over 30 years.

Lake Mead is artificial. It will 'ebb and tide' as those who control it see fit. Therefore, it's not a great indicator of environmental collapse.

Not a great indicator of environmental collapse, but a good one for a drought. I would imagine the people in charge of that artificial lake would love it if it would tide just a bit more at this point.

But I don't think they have as much control you suggest, I do believe they have obligations of letting amounts of water to go downriver for the farmers south of the dam.

I lived there for a number of years, the animated map does not do justice of showing how low the lake is, if you visit the dam you can see the water lines on the dam wall (hah!) and the shores around it. It's not just how much width the water has receded, but how deeply as well.

Receding ice sheets don't terrify you? The felling of rainforest, the Earth's inhaler of carbon dioxide. Disappearing.

All because of one species. Human beings. That is a chilling.

I don't mean to diminish your point, as I fully agree with environmental concerns.

But I laughed when you said it's chilling that the ice sheets are receding.

Heh, I didn't even notice that.

Sorry to burst your bubble, but you may be vastly overreacting.

Talking about what's happening in both the Atlantic ice sheets and the Antarctic ice shelves can become complicated, and as far as I can tell (someone please correct me if I'm wrong) not definitive by any means.

However, rainforests are by no means the "Earth's inhaler of carbon dioxide (and by extension I took that to mean 'oxygen producer' as well)". According to many sources (http://en.wikipedia.org/wiki/Rainforest#Tropical, http://www.columbia.edu/cu/21stC/issue-2.1/broecker.htm, http://www.iub.edu/~act/files/publications/1992-93/93-03_Def...), rainforests do not contribute much to global oxygenation.

In fact, organisms like the prochlorococcus http://en.wikipedia.org/wiki/Prochlorococcus have been theorized to be responsible for at least 50% to 60% of the world's atmospheric oxygen (http://www.nature.com/nature/journal/v424/n6952/full/nature0... there's a paper in the references there which has that statistic, but I don't remember which). Today, these microbes are still hard at work, churning out oxygen and while some mistakes have been made (iron seeding, etc) they're still the most populous microbe on the planet.

I would also contest the point about human beings. (This is my opinion talking now). I will not disagree that the earth's climate is changing rather rapidly (relative to the measurable past). I will argue though that it is arrogant to presume that humans are the root cause. On a micro scale, humans have been rather destructive to specific ecosystems. However, I have yet to see convincing proof that humans can effect climate change to this magnitude on a macro scale.

Humas produce on the order of 3.10^13 kg of CO2 [1]

Atmosphere weighs 5.1 . 10^18 [2] so the CO2 we produce is 1/100000 (or 0.001%) of the total weight.

Atmosphere contains 0.046% CO2 by weight [3]. So, next year, it's going to be 0.047%

[1] http://www.epa.gov/climatechange/ghgemissions/global.html

[2] http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.htm...

[3] http://www.engineeringtoolbox.com/air-composition-d_212.html

So you are saying we increase the relative amount of CO2 with 2% (47/46) per year and try to brush that away as peanuts?

I'm sorry you understood it that way. I wanted to point out that it is in fact a pretty big deal! Human produced CO2 (mainly from fossil fuel burning) is changing the global environment pretty dramatically. nathannecro wanted to see evidence that we're doing something on the macro scale, here it is.

Your argument is completely spurious - the relative weight of our emission is not what determines if we change the climate. It would be like saying the average human weighs 70Kg so 500micrograms of LSD will do nothing as it is only 7.14^-7% of the body mass.

97% of climate scientists agree that the current climate change is anthropogenic: http://theconversation.com/its-true-97-of-research-papers-sa...

It's not even the first review. How much more proof do you need?

I think it's arrogant to ignore scientific consensus.

I'm fully aware of the PNAS paper (and others like it which have been published). Let me point out a few other times in history where scientists, without clear evidence for their beliefs, were wrong:

When Galileo championed the idea of heliocentrism, the vast majority of all other astronomers during his time opposed his views. http://en.wikipedia.org/wiki/Galileo_Galilei

The idea of phlogiston was quite prevalent in the chemistry community for about a century before it was definitively proved to be a pile of combustible turds. http://en.wikipedia.org/wiki/Phlogiston_theory

Even recently, in the early 20th century, physicists believed that: a) The smallest particle of matter (the atom) had been quantified, measured, and fully explored. b) There was no more to discover in the field of physics. Clearly, they were wrong.

Let me rephrase my objection more clearly. I believe that the Earth's climate (across all biomes) has been rapidly shifting over recent time. I know that humans can impact local ecosystems and one of the results is a shift in local climate. I have yet to see evidence for (cum hoc ergo propter hoc is a danger when looking at studies) humans causing climate change on a global scale.

This does not mean that we should stop our efforts to prevent deforestation. Nor does it mean we should ignore local environmental disasters, but linking local impact to global impact has not been done definitively yet, so as a scientist, I question that belief. It is not out of arrogance that I question, but out of the desire to be a better scientist. I am trained to base my beliefs in: Hypothesis -> Evidence -> Examination -> Belief. What we do have currently is a very good "guesstimate" hypothesis (we observe that humans can cause local ecosystem shifts). What we do not have is evidence. And thus, we do not have the opportunity for discussion or the transition to belief.

I don't believe any of this is true.

> 97% of climate scientists agree that the current climate change is anthropogenic

No doubt something close to 100% of astrologers agree that the stars effect one's personality.

AFAICT, almost anyone educated in climate science over the last few decades has been taught to assume anthropogenic climate change as a given. Furthermore, both the folks whose research supports the anthropogenic hypothesis and those whose research refutes it have significant incentives (financial, social and religious) to so find. I don't trust the lot of 'em as far as I can throw 'em.

"However, I have yet to see convincing proof that humans can effect climate change to this magnitude on a macro scale" Ok, let's start with something easier. Can we agree on the magnitude of the global changes that humans caused on the extension of forests and on the concentration of CO2 in the atmosphere?

Ice sheets don't concern me one bit. Ice and cold is definitely one thing humanity can do with less of.

Felling of rainforest is more of a concern for me. Especially when it is for palm oil, soybean and sugar cane plantations to produce bio fuel. That one makes me quite concerned.

"Ice sheets don't concern me one bit. Ice and cold is definitely one thing humanity can do with less of."

You say that as if the melting of the ice sheets doesn't have its own downstream effects on the world's climate and ecosystems.

> The felling of rainforest, the Earth's inhaler of carbon dioxide.

Actually, if (and I'm aware it's a big if) they cut down the rainforest and plant new trees there, it's actually a net win for carbon dioxide.

There is nothing better for carbon dioxide than cutting down a tree and using it for wood or paper AND replacing it with a new young tree.

Of course I don't know if they are actually doing that.

And it's likely to be bad for the animals that live there.

Best would be to thin the forest, and plant new trees as you go. (Or let the forest self seed.)

> Actually, if (and I'm aware it's a big if) they cut down the rainforest and plant new trees there, it's actually a net win for carbon dioxide.

I believe it depends on what you do with those trees. A lot of the deforestation occurs through burning. An area is logged (bad for the ecosystem, not so bad for carbon), then its cleared by burning (bad for carbon) to make room for farmland.

> to make room for farmland

(bad for carbon if they feed livestock or use fertilizers there)

Depends on the soil. Rain forest soil is not very fertile, and the vegetation is quick to recycle - most nutrients are in the very top layer and in the plants at all times. Thus if you take away the trees without letting them rot and release the nutrients you could run into problems very soon. In mid-latitudes, on the other hand, it's not as big a problem because the recycling is a lot slower and the reservoir is far greater.

90% of species that ever lived on Earth are gone without any help from humans.

and we're rapidly getting through the remaining 10% too.

so if it's fine with the vanished 90%, why should one be bothered about 10%?

Because we are in that remaining 10%, as are all of the species we rely on for food. Most people have an interest in the continuation of humanity, at least in theory.

Most people is interested in continuation of themselves and their close relatives. Seven billion of people, driven by this interest, form a hivemind that dictates their own fate. Should it be the extinction of 9.999% of species - so be it.

The rainforest's use up almost all of the oxygen that they put out. As far as carbon dioxide they are pretty net zero in the end. It is the Algie blooms that produce the oxygen surplus. While fun to say, rainforest's are not the earth's lungs. But don't take my word for it, checkout either the very good video (or search the transcript for "lungs") http://www.pbs.org/wgbh/nova/space/earth-from-space.html

Too late to edit my comment but I should have emphasized "all". Meaning, yes, some are terrifying how natural resources are being lost but others are just amazing and impressive without being terrifying at all.

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