Climate Change / Global Warming

[FrancisTapon]

I wrote a couple of controversial articles about on the climate change issue while I was hiking the CDT.

One is a debate with a T-Rex.
The other offers some suggestions on what we should do about climate change.

Tell me what you think here!

[ben]

okay, i'll bite. it's been a while since i read your piece on climate change, but one thing you said has been nagging me. you mentioned that because we're so bad at predicting the weather over the course of the next few days (will it rain, will it be sunny, will the hurricane make landfall), we shouldn't trust people who claim to be able to predict what the weather will be like in 50-100 years. i think that's misleading. it seems to me it would be much easier to predict broad trends, like climate change, than to predict the details, like how much it's going to rain tomorrow.
i enjoyed reading your piece, was a little annoyed at some of it, but enjoyed it. i was glad to see your follow up piece in which you said that just because climate change might ultimately improve biodiversity planet-wide, that's no reason to hope and pray for, or heaven-forbid deliberately further, climate change.
i realize there are lots of different climates for this planet to choose, but we were born into this one and i think we'd be well served to try to maintain it to the best of our abilities.

ben

[FrancisTapon]

okay, i'll bite. it's been a while since i read your piece on climate change, but one thing you said has been nagging me. you mentioned that because we're so bad at predicting the weather over the course of the next few days (will it rain, will it be sunny, will the hurricane make landfall), we shouldn't trust people who claim to be able to predict what the weather will be like in 50-100 years. i think that's misleading. it seems to me it would be much easier to predict broad trends, like climate change, than to predict the details, like how much it's going to rain tomorrow.
ben

I used to believe that too, and that makes sense. However, then I started investigating our past climate changes and trying to understand why they occurred. That's when I learned the bad news: we don't know why it occurred.

If you can't explain the past, how can you predict the future?

Imagine someone telling you that the Dow Jones will hit 15,750 in June 2008. If that person can't explain why it went down in Oct 1989 or went up last week, then how much credence would you give his prediction?

Although scientists have ideas why Earth's climate has fluctuated so violently over the last billion years, there is no conscensus on the root cause(s). Therefore, I have little confidence in their predictions.

Finally, notice that scientists are no longer calling it "global warming." Instead, they call it "climate change."

That's a cop out. They're saying: some places might get hotter, others cooler; some might see more precipitation, others less; etc....

The vagueness of "climate change" means they'll be right no matter what, since climate has always changed (both in the short and long term). That hesitancy proves that they don't know what will happen, and that they don't understand the causes and effects of climate change. Until they understand all the correlations, it's hard to make accurate predictions.

i enjoyed reading your piece, was a little annoyed at some of it, but enjoyed it. i was glad to see your follow up piece in which you said that just because climate change might ultimately improve biodiversity planet-wide, that's no reason to hope and pray for, or heaven-forbid deliberately further, climate change.
ben

Yeah, it's just my selfish perspective. I just don't want to be part of the generation that undergoes the disruption that climate change will cause.

If I had children, I might be more willing to put up with it, knowing that my grandchildren would probably have a better world. But since I don't have any children (that I know of), I want to enjoy my life.

i realize there are lots of different climates for this planet to choose, but we were born into this one and i think we'd be well served to try to maintain it to the best of our abilities.
ben

I used to think like that too, but lately I'm starting to believe that maintaining the status quo would be the most unnatural thing we could do. After all, the climate has never, in all of history, been stable. It's always changed both on a short term and long term. Therefore, to bio-engineer the Earth to force it to stay with the same climate would be doing something quite unnatural.

Lastly, we (homo sapiens) were born into a world that was in a glacial period of an ice age. About 10,000 years ago it warmed up dramatically. Should we preserve it the way we found it, prior to 10,000 years ago? Should we try to create a global freeze to return it to the natural condition we found it in when we came out of Africa over 100,000 years ago?

Thanks for your sharing your thoughts Ben!

[Brennan]

First off, I would like to say that I really liked what Ben had to say. He got his point across while still staying open minded, which is what a discussion board is all about. Secondly, Francis... well, you definitely have your convictions, which is good, but your stubbornness is causing you to contradict yourself. How can you say we can't predict broad trends, and then you yourself predict broad trends in your 'Human vs. T-Rex' dialogue. The T-Rex comments that "we are due for another cooling". This seems like a climate change forecast to me. Perhaps you're just playing the devils advocate, which is fine. Ultimately, you both made valid points.

Personally I would just like to say that we need to reduce our carbon output for two different reasons.

1. So that the U.S. economy isn't controlled by gas prices.
2. I've lived in Colorado for 20 years, and every year the smog gets worse. I just want to see the mountains again!

[FrancisTapon]

First off, I would like to say that I really liked what Ben had to say. He got his point across while still staying open minded, which is what a discussion board is all about.

Agreed!!! I apologize if that didn't come across in my reply to Ben. Because I take unconventional positions, I expect many people to disagree with me. I welcome criticisms, because it sharpens my thinking.

You're absolutely correct that mature and open minded debate is what this discussion board is all about. I'm thrilled that everyone who has posted so far is more mature and open minded than me!

Secondly, Francis... well, you definitely have your convictions, which is good, but your stubbornness is causing you to contradict yourself. How can you say we can't predict broad trends, and then you yourself predict broad trends in your 'Human vs. T-Rex' dialogue. The T-Rex comments that "we are due for another cooling". This seems like a climate change forecast to me. Perhaps you're just playing the devils advocate, which is fine. Ultimately, you both made valid points.

You're right that I'm being somewhat hypocritical by making a climate predicition after saying that climate is hard to predict. Let me clarify:

* I'm not saying that we can't predict broad trends. I'm just saying that we haven't mastered that science yet, as evidenced by the myriad of climate predictions out there (e.g., some scientists say that the increased greenhouse gases will warm the Earth, while others predict that it will plummet us into an ice age; some say increased precipitation, others decreased precipitation). In short, it's all over the map at this point, probably like our 3 day forecasts used to be 100 years ago. Now we make accurate 3 day forecasts. I'm confident that we'll learn how to make great 3 century forecasts in our generation. We're just not there yet.

* When the T-Rex predicted that "we're due for another cooling," he should have prefaced that prediction with, "If humans weren't around...." I believe 90% of climate experts would agree with that statement, because our glacial and interglacial periods during our current ice age have always been so predictable and steady (100,000 year cycles). Therefore, it stands to reason that those cycles would continue throughout this ice age. These cycles are almost as reliable as the rising of the sun, so T-Rex wasn't making a wild prediction when he said that "were due for another cooling." Of course, at some point this ice age will end, but if it's like other ice ages, it will last for another few million years, punctuated by interglacial and glacial periods. T-Rex should have explained all this, but his command of the English language is rather weak....

Personally I would just like to say that we need to reduce our carbon output for two different reasons.

1. So that the U.S. economy isn't controlled by gas prices.
2. I've lived in Colorado for 20 years, and every year the smog gets worse. I just want to see the mountains again!

I completely agree with #1. In fact, read my "article about what we should do about climate change" and you'll see that I wrote:

* If gas was $6/gallon, car manufacturers would create cars that got 100 mpg and our dependence on unstable oil rich regimes would go down.

That's effectively saying what you're saying. I'm tired that Venezuela, Russia, and Middle Eastern countries have such an important role in our economy.

#2 That is my #2 on my page too, when I wrote:

2) POLLUTION: Lowering pollution is nice. Decreasing greenhouse gases usually means decreasing pollution, which is a negative externality that governments rarely try to recover. By fighting climate change, we're indirectly fighting pollution. Although we must pollute, it would be good to charge the polluters, even if that means that we all have to pay more for our goodies.

In conclusion, thank you for your great feedback and keeping me honest.

[tacomabike]

They just discovered that humans don't cause global warming ... guess you were right after all !Steve

----------------------------------------------------------------------

http://www.digitaljournal.com/article/277236


As the carbon dioxide management bill - aka cap and trade - looms in Congress, a new study emerges that ends the scientific debate on the central causes of ice ages and warming periods on Earth.

Former U.S. Vice President Al Gore is fond of saying that the scientific debate on global warming is over - and while he may now be correct in the fact that a debate has come to an end, the central cause behind climate change does not support the carbon cap legislation that is being cobbled together by Mr. Gore and his Democratic allies in the U.S. Congress.
The earth cools and warms due to the wobble in its rotation and axis - factors in large-scale physics that human beings cannot control. These are factors, also, that human beings did not cause.

.... The findings from the research team at Oregon State University

[FrancisTapon]

Steve: Thanks for posting the link to that article! The article's title is wrong, since no article will end the debate on global warming!

I agree with this part of the article:

"Sometime around now, scientists say, the Earth should be changing from a long interglacial period that has lasted the past 10,000 years and shifting back towards conditions that will ultimately lead to another ice age – unless some other forces stop or slow it," Science Daily reported.

This is exactly what T. Rex mentioned in my Dino Debate on Climate Change when he said: "It’s been 10,000 years since the last glacial period and 18,000 years have passed since the last maximum, so we are due for another cooling."

This corroborates with the fact that prior to the human-induced global warming of the last two centuries, worldwide climate has been cooling naturally for several thousand years.

I also encourage you to listen to the podcast "An Appeal to Reason Podcast." Skip the boring 10 minute introduction. Start listening once the actual speaker starts. He's followed by someone who represents the conventional wisdom of the climate debate.

Although it's nice that you say that I was "right after all" that "humans don't cause global warming," I'm never said that they don't. I agree that humans change our global climate (along with microorganisms, cows, and ants). I'm just questioning if we are the main cause for climate change or if we can overnight other natural processes (like the earth tilt) just by tossing up a few billion tons of greenhouse gases in the air. In short, I'm appealing to reason, balance, logic, and skepticism.

[FrancisTapon]

Given this news from the BBC, it shows that we've still got a lot to learn. That's why it's important to be vague and just predict "climate change" and not "global warming." That way you're guaranteed to be right.

That is, unless something truly bizarre happens, something that has never occurred in Earth's history: that the climate doesn't change. Then we can be sure that humans must have something to do with it!

[fmclean]

Well, given this news from the BBC, http://news.bbc.co.uk/2/hi/science/nature/8377128.stm, it turns out that the claims that temperatures haven't been rising were in fact wrong (sometimes even the BBC makes mistakes).

Predicting climate change is only vague in as much as they don't know what the exact effects will be, nor can they pinpoint exactly where they will be felt. Whether or not climate change will happen is no longer a prediction; it will happen and already is happening.

As you pointed out in another section of the forum, scientists as well as other academics, politicians, environmental organisations/NGOs (particularly in Europe), rarely call it "global warming" anymore; instead "climate change" has now become the accepted term. One of the reasons for this is that calling it "global warming" is misleading.

The general public doesn't really understand the concept of global warming, so when they hear that global average temperatures will increase by 2C degrees (or 4C or 6C or whatever), they just assume that across the board everywhere will get warmer by 2C degrees. However, that is not at all the case. Some places will get colder, some hotter, some wetter, some drier. In some places the temperature difference might be more like 6C or 8C - or as much as 10C or as little as 0.5C - even though the global average change is 2C. There will also be more extreme weather events, such as hurricanes, tornadoes, freak snowstorms in summer, temperatures above 20C in the winter, excessively heavy rainfall in short periods of time, i.e. last week in Cumbria in Northern England where record rainfall caused flooding with water levels reaching over 2.5 metres (8ft 2in). So although the projected increases in temperature don't sound like much, the local and regional consequences could/will actually be quite significant.

Due to the physical geography of our planet, i.e. mountains, oceans, rivers, plains, etc., as well as differences in latitude/longitude, there are a wide range of diverse micro-climates across regions, countries and continents. For example, weather patterns on the West Coast of North America are quite different from those on the East Coast. The weather in Southern Europe is also very different from that of Northern Europe. Likewise, the weather in Goa is totally different than in Dharamsala. And don't forget that when we're suffering through -20C temperatures and whiteouts in January, the people in Sydney are baking at the beach. So of course the effects and impacts of climate change will be felt differently in different regions of the world. It would be naive to believe otherwise.

Contrary to what you have previously suggested, calling it "climate change" is not a cop-out, nor is it a matter of hesitancy, keeping things vague, or trying to ensure that they are right regardless of what happens.

We can expect that worldwide there will be major impacts due to (anthropogenic) climate change in the next 20-40 years. So based on your current age and the average life expectancy for a US male (currently 75.65 years), it would appear that you already are one of the generations who will be undergoing the disruptions of climate change. And based on this BBC article, http://news.bbc.co.uk/2/hi/science/nature/8375949.stm, you might even witness or experience some of those disruptions yourself during your travels in Africa next year.

Fiona

[FrancisTapon]

Well, given this news from the BBC, http://news.bbc.co.uk/2/hi/science/nature/8377128.stm, it turns out that the claims that temperatures haven't been rising were in fact wrong (sometimes even the BBC makes mistakes).

Predicting climate change is only vague in as much as they don't know what the exact effects will be, nor can they pinpoint exactly where they will be felt. Whether or not climate change will happen is no longer a prediction; it will happen and already is happening.

Fiona, has climate change ever NOT happened?

Climate has always changed, from hour to hour, day to day, century to century, and millennium to millennium. Moreover, it's also changed quite fast, without human help. My favorite example is the asteroid that knocked out the dinosaurs, which changed our climate overnight.

Many scoff at such an example, saying it's not representative of typical pre-human-induced climate change, which takes a LONG time. Does it really?

The last glaciation ended about 11,000 years ago. Yes, humans were around, but there weren't many and nobody had an SUV. Most climate scientists agree that we went from having glaciers covering half of Europe to today's environment in just 20 years! Bill Bryson mentioned this in his History of Nearly Everything book, where he points out that we exchanged the climate of Sweden for that of Texas in just about 20 years.

Please read this academic paper (or at least the abstract) to learn that previous major climate changes were much faster than many people might imagine. It concludes, "From present understanding of the record of the last 150,000 years, at least a few large climate changes certainly occurred on the timescale of individual human lifetimes, the most well-studied and well-established of these being the ending of the Younger Dryas, and various Holocene climate shifts. Many other substantial shifts in climate took at most a few centuries, and they too may have occurred over a few decades."

Another researcher points out that the last cold period (13,000 years ago) took just six months to blow in.

In short, climate change not only happens without our help, it also can do it quite quickly, within a human lifetime.

Since we hardly understand why any of this happens (and we can't seem to predict the weather just 5 days from now), then it's a bit presumptuous to believe we have a crystal ball that can accurately predict our climate 10, 100, or 1,000 years from now.

The general public doesn't really understand the concept of global warming, so when they hear that global average temperatures will increase by 2C degrees (or 4C or 6C or whatever), they just assume that across the board everywhere will get warmer by 2C degrees. However, that is not at all the case. Some places will get colder, some hotter, some wetter, some drier. In some places the temperature difference might be more like 6C or 8C - or as much as 10C or as little as 0.5C - even though the global average change is 2C. There will also be more extreme weather events, such as hurricanes, tornadoes, freak snowstorms in summer, temperatures above 20C in the winter, excessively heavy rainfall in short periods of time, i.e. last week in Cumbria in Northern England where record rainfall caused flooding with water levels reaching over 2.5 metres (8ft 2in). So although the projected increases in temperature don't sound like much, the local and regional consequences could/will actually be quite significant.

You make a great point. Climate will CHANGE. That means for some it will change for the worse, for others it will change for the better.

- A desert may blossom thanks to climate change
- A tundra might explode with trees, arable land, and wildlife
- Antarctica might finally be livable again (it used to have 30 meter trees covering it 45 million years ago during the Thermal Maximum of the Cenozoic - and yes, Antarctica was located at the south pole back then too, so it was really hot overall on this planet).

The news focuses on the negative about climate change. I like a more balanced approach. Why don't we consider the millions of species that will benefit from climate change?

Yes, many species will die. Is that news? Not really. 99.99% of all species that have ever lived are extinct. Many were knocked out by climate change, both the slow and the fast kind. Species come and go, but life goes on.

Climate prophets stupidly claim that nature "can't handle such fast climate changes." However, all the life on this planet is living proof that nature can certainly handle rapid climate change! Consider the hundreds of wild temperature swings (far worse than a mere 6 degrees) that the Earth has gone through. Many of those swings occurred over just a few decades, and some even happened overnight (Dino extinction, Yellowstone's toxic eruptions, etc.). Yet, we're still here.

In fact, evolutionary biologists rejoice that these punctuated, dramatic, and quick temperature swings have occurred. The world wouldn't be the same without it. Without climate change, including swift climate change, humans (and many other species) wouldn't be around here today. We'd still be bacteria, which brings up....

Even if we are causing the current climate change (which I agree is probable) and we end up killing lots of species, it's not unprecedented. We'll just be following in the footsteps of our ancestors. No, I'm not talking about early humans who hunted much of the Earth's mega-fauna to extinction.

I'm talking about our real early ancestor, the cyanobacteria. Our common ancestor was responsible for the Oxygen Catastrophe 2.4 billion years ago. Alas, our great-granddaddy was the biggest mass murderer in Earth's history. For all the species living on the planet, oxygen was a deadly poison gas. Did our relative care? No, he just kept burping and farting oxygen every time he digested water. The climate has never been so drastically transformed by any other living organism. The cyanobacteria managed to kill nearly every living thing on the planet. It makes our human touch seem delicate.

Life does what it must to reproduce, damn everyone else. We're no different than our uber-genocide producing ancestor. Perhaps we ought to be wiser, but we're not.

Contrary to what you have previously suggested, calling it "climate change" is not a cop-out, nor is it a matter of hesitancy, keeping things vague, or trying to ensure that they are right regardless of what happens.

Perhaps, but my main point is that it's not a very interesting term. Such a prediction is like saying "I predict the sun will rise tomorrow."

Climate has always changed, and, as I mentioned earlier, the climate has also changed quickly (all on its own, without us nasty little humans twisting its arm).

Most importantly, life on Earth has dealt with it just fine, thank you. If it could survive the Snowball Earth climate (where the whole Earth was frozen about 1 billion years ago), and it could survive the Great Oxygen Catastrophe, and it could also thrive in the Thermal Maximum of the Cenozoic, then I think it can handle a 2-10 degrees warming.

Of course, some humans may not like it. On the other hand, others will. Again, the media ignores all the humans who will benefit from climate change. People who live in the Nevada desert, the Canadian tundra, or the Australian outback may all benefit as their climate change to something that humans generally prefer (people in those areas may see their climate get wetter, warmer, or cooler, respectively).

First, the media told us it was global warming. When they realized that half the industrialized world would be grateful for a couple of degrees of warming, they switched to "climate change", but with a twist. They focused on change...for the worse. When the doomsday preachers warn about climate change, they imply that "where you live, your climate will get worse." Although nobody knows for sure, this is extremely unlikely.

A much more likely scenario is that some people will enjoy better weather, while others will suffer worse weather. And some won't see any substantial change at all. Hence, winners and losers.

Moreover, who decides what's bad anyway? A snowmobiler will hate that Alaska warms up, while an Alaska farmer will love it. One woman will cry if Arizona gets drier, but an environmentalist will be happy that the Desert Fox has a wider habitat. A beach bum will hate if Bali gets cooler, but those who suffer from heat strokes will love it.

Although nobody really knows our climate future, there are enough predictions out there that in 2020 or 2070 many people will be able to say "I told you so." Meanwhile, the rest will quietly change the subject.

That's why I don't make predictions, other than the obvious one that will always be right: climate is changing and will change in the future. And it may change quickly or slowly. And for better or for worse. And don't ask me why.

Once the news says that climate has stopped changing, then I will be very worried. That would be a once-in-an-Earth-time event.

Finally, I am not suggesting that we should ignore climate change. I have written an article describing what we ought to do about climate change.

My main point here is that we should be skeptical and humble during any climate change debate.

Most of all, we should have a wider perspective. This wider perspective includes considering longer periods than the last 150 years or even the last million years. It includes considering ALL species (both the winners and losers). It includes considering ALL humans (both the winners and losers). With such a broad perspective, we might have a more intelligent debate.

Thanks for thoughts!

[FrancisTapon]

Is this bad news or good news?

Researchers are finding that grizzly bears are moving into a new land: polar bear territory. While some might spin this news as bad news (i.e., polar bear habitat is shrinking), one could easily interpret it as good news (i.e., grizzly bear habitat is increasing).

It's an illustrative data point that shows that climate change will not just bring bad news. As glaciers melt, deserts expand, and the arctic warms, there will be winners who will love all the changes.

The media will focus on the bad news since that's what sells, but let's hope that thoughtful people consider the flip side.

Similarly, as an Eskimo's livelihood get disrupted by the vanishing ice, there will be enterprising Eskimos who will grow crops and hunt animals that previously weren't possible.

Finally, it's certain that during the 21st century the net number of species on the planet will decline. Some will blame climate change, but the biggest reason will be that humans, who will reach 9.5 billion in 2050, will consume more and more resources, encroaching more and more on wildlife habitats.

If all life on Earth could vote, what would they prefer:

a) Human population declines to 1 billion and the planet warms 2 degrees.
b) Human population of 9.5 billion and the planet temperature stayed constant.

I suspect most would pick (b).

In conclusion, climate change will hurt some species and help others. The reason there will be a net negative impact on life on Earth won't be because temperatures are going up, but because humans are going up.

[FrancisTapon]

Look at this chart to see how much warmer the Earth has been and to see how we are currently cooler than average. The present day is on the far RIGHT of the chart.

You rarely see this chart because it covers 500 million years, instead of just 500 years or 500,000 years, which is what the doomsday climate changers want you to focus on. Complex life took off 500 million years ago, so it's a useful period to start measuring.


Scientists struggle to explain the root cause of why the Earth temperatures have fluctuated so much. They might say:

- It's because massive volcanic activity happened.
Great, but why did massive volcanic activity happen and might it happen again soon?

- It's because of the Milankovitch cycles.
Great, why does the Earth tilt or change its orbit and might it happen again soon?

Science doesn't have confident answers on such questions yet. One day they will, but so far we're not sure.

Wouldn't it be funny if scientists in 2091 look back at 2011 and say, "If those guys only had the proper data, algorithms, and models, they would have seen that the Earth was heading for a glacial cycle, and that to slow down the cooling they would have to pump MORE greenhouse gases (not less) to keep the temperature stable."

I'm not betting they will say that, but I will bet that future scientists will giggle about some of the things we believe today just like we giggle at some of the things scientists believed 100 years ago.

I'm not arguing that the present-day scientific consensus (that the Earth is warming and it's our fault) is wrong. It's probably correct. I'm just trying to remind ourselves of 6 facts:

1. Climate science is still a new science. We have a lot to learn, so let's not get too cocky and think that we know it all. Remain skeptical and critical.

2. The Earth has been far warmer and has thrived in such conditions (think of the Devonian or Jurassic period).

3. The climate has changed dramatically (within a human lifetime) many times and life goes on.

4. Extinctions are normal. 99.9% of all species that have ever lived are now extinct. We've had 5 massive extinction events and we're having another now. Life on Earth is constantly reinventing itself.

5. Humans have survived at least two major climate change events:

a. The end of the last glacial period, about 13,000 years ago, when sea levels quickly rose over 60 meters. (The most dire current predictions say we may see a 1 meter rise in 100 years.)

b. About 75,000 years ago, the Toba supervolcano killed about 2/3 of humanity (that's like 4.5 billion dying today). But we (and the rest of the planet) shrugged it off and kept going.

What's important is that in those prehistoric days, primitive homo sapiens didn't have weather satellites forecasting the climate, or dams/dikes to manage flooding, or boats and helicopters for evacuation, or global commerce to help distressed areas, or food storage to minimize food shortages, or 7 billion people running around to absorb the blow to the species.

Instead, humanity was a fragile flock that could have easily been wiped off the Earth. Our ancestors were stubborn and survived. So will we.

6. Many humans and species (both plant and animal) will BENEFIT from climate change (I've discussed this more thoroughly in an earlier post). The July 5, 2010 audit of the IPCC report on climate change blasted the scientists for accentuating the negative and deemphasizing the positive. Let's hope that we begin to celebrate the upsides of climate change and not just focus on the downsides.

If you care about want to stop climate change: beg your politicians to impose a stiff greenhouse gas tax and child tax (to discourage reproduction).

Otherwise, shut up and enjoy the warmer weather.

[aalundexy]

Why is there a Global Warming section in yahoo answers when it has never been proven? Scientists who believe in global warming have concluded that the future of the world is in danger and that global warming may contribute to a minimal (slight) acceleration of a normal process of natural disasters.

[FrancisTapon]

Just because there is a section in Yahoo Answers about global warming doesn't mean that anything has been proven. It's just a place to ask questions and read a variety of answers.

What's one species' disaster is another species' glory.

[FrancisTapon]

I answered my own question incorrectly when I wrote:
[quote="FrancisTapon"]Is this bad news or good news?
If all life on Earth could vote, what would they prefer:

a) Human population declines to 1 billion and the planet warms 2 degrees.
b) Human population of 9.5 billion and the planet temperature stayed constant.

I suspect most would pick (b).
/quote]

I meant (a).

Most species would be better off if there were fewer human encroaching on their territory.

Some species (especially domesticated animals and human crops) would suffer a population collapse if human population collapsed.
However, most species would thrive.