The Earth has likely been fully enveloped in ice and snow before, you should know that there were several ice ages and the one our ancestors survived was one of the smaller. Damn if we had another snowball earth we would have never existed. When a megavolcano erupts it can spew it ashes so high that it envelops the whole planet and blocks sunlight and that is what causes cooling on a global scale. 

Snowball Earth is actually a highly disputed theory. But if it happened my main point still stands: the climate changes took place over tenthousands of years. Small local changes through vulcanic eruptions may have happened faster. Now we have global changes in the timeframe of decades. This is new.

Compared to the rest of Earth's history, doubling our current CO2 levels is still only a fraction of when life was still sustainable at peak CO2 levels ... 

Actually, it's a good thing that the arctic region is getting warmer since greening indicates more arable land to use! With the arctic getting warmer it opens up the two biggest countries such as Canada and Russia to farming and inhabitation ... 

I don't know enough about Australia to make an educated comment on it so I'll leave this statement as is ... 

@Bold Highly dependent on the conditions. In earth's case there's virtually no way to forseeably triggering a runaway greenhouse effect like in Venus's case since it's so much more closer to the sun and had a very thick atmosphere (at least 100x more than earth's) to begin with ... 

There's no need to continue fear mongering doom and gloom about the survival of human species because of a 1-2 degree celsius increase. It's been physically checked out to be implausible ... 

More pressing issues to worry about in our lifetimes and very likely the next 10 generations lifetimes than climate change ... 

Nothing because we'll run out of petrochemicals to burn before then ? So far we've only proven 100 years worth of economically recoverable coal reserves and 50-70 years of economically recoverable oil/shale reserves. It's only getting harder to find ways to recover fossil fuel reserves all the while the rest of the world is developing so energy consumption will also keep exponentially increasing ... 

Humanity won't be burning fossil fuels for a long time relative to their whole species existence. It'll be just a short stint ... 

Correct.
But life was also very different back then and life had time to adapt.

Meanwhile large swathes of the Americas, Europe, Oceania, Africa could potentially become inhospitable.
Plus sea levels will rise causing the displacement of millions on islands and coastal regions.

It's far from a "good thing".

Probably be wise. Considering I do live here and work against the environment in various scenarios. :P

Runaway? Maybe. Maybe not.
But there is an exponential increase in damage to the Earths ecosystems for the CO2 we emit.

Will we have a planet like Venus? Shit no.
But that isn't what I have claimed or ever claimed, but an increase of say 6'C would place extreme summer temperatures at almost 60'C here (140.0 °F) - If you think that is inconsequential to life, then I have a few things to tell you... Because even on 50'C days (122.0 °F) the tar on roads starts to melt, people get hospitalized/die.

I have real world experience of what heat does to an individual, do not just shove it aside casually.

We went from 280PPM to 400PPM with a corresponding increase of 1'C. Bulk of emissions were done within the last 100 years.
And our emissions rate is only continuing to increase, especially as China is undergoing it's industrial revolution.

In 50 years we may have another increase of 1C. - Which means more CO2 will be released from our arctic regions and oceans. (It's like opening a can of coke.)

The issue is... Temperatures will continue to rise, it's not going to stop because people think "We will be alright".

And even when we stop emitting, temperatures will continue to rise as our oceans and arctic regions continue to release more CO2 due to the warmer temperatures.

Governments across the world elect individuals to take on various roles. Pretty disingenuous to think we only have a capacity to focus on one or two issues.

Climate change is a long term issue, the sooner we start, the less successive generations need to do.
Besides, money can be made in tackling climate change... Leverage all of the capitalisms.

Well. Not entirely accurate.
As the arctic regions decline, more opportunities for oil extraction occurs.

However... And this it the big kicker. We can grow oil.

At the moment I have been heavily involved in trying to stop Statoil from drilling for oil in the Great Australia Bight, because... That is one of the most pristine places on Earth... And it is right at my back door. - Got the local councils in my region onboard.

It's easier for people to understand how everything is connected in some way, when your knowledge is spread out and your capable of doing more than just 'a few things'. Not that long ago, people were taught more so in a way to be a jack of all trades, yet today, people are taught to be really good at one or two things, and not taught anything else, because they are told they don't and shouldn't need to. When all you know are a few things really well, trying to understand how and if everything else fits together seems more complicated. It makes the world more efficient in terms of business, but things like science, politics, law, etc, really pay the price because of this.

After spending a lot of time in the renewable energy industry, I don't think we should just blindly keep pumping out CO2 and assume it will never become a more serious problem, because while the greening of Earth is good in some ways, its dangerous in others. More plants to absorb CO2, but also release it, more food for people to eat, but also more things like ticks carrying lyme disease, spread far beyond the places they inhabit now. While more CO2 leads to more evaporation, so does the amount of sunlight itself. While we can't do all that much about blocking the sun, we can do something about CO2 output. Plus crude oil isn't exactly something we have an endless supply of, and we're going to need it for certain products longer than we will need it for others like gasoline.

I'm definitely a believer that we should try and cut back on CO2 emissions as much as possible without harming the economy too much, but I don't think we need to be freaking out on the level that some people do. Companies like Tesla with their cars and batteries are pretty much at the point where they've made enough of an impact that the world will end up following their lead. Many companies are already working up to that. I wouldn't be surprised if by 2040 every single auto sold worldwide is electric or hydrogen by then. Another 10 years of solar and storage improvements, and having affordable solar and battery packages for rooftops should start to become the norm, which also means the grid can shrink considerably and power plants can burn less fossil fuel. Hopefully by then we've come up with a cleaner mass power generation solution. Hydrogen would be the way to go if they can get the cost down but right now I believe it's around 4X, so they have a ways to go. There's also nuclear fusion, but I wouldn't count on that.

The vast majority of life can still adapt. Most simple lifeforms like bacteria, protists, fungi, and plants aren't going anywhere anytime soon since they are much less sensitive to climate conditions. Most of the animals that already have a conservation status classified as domesticated or least concern will still likely have the same status as they did before 100 years later ... 

It's a pretty huge stretch of a scenario though since we'd have to at least find 10x higher fossil fuel reserves to burn before it remotely becomes a problem because right now at our current level we're still under the optimum level of CO2 concentrations for plant life respiration ... 

So far from the NASA data, there's no panic or alarm of large patches of land becoming less arable ...  

I'm not sure if we can just make a simple quantifiable statement that there is an "exponential increase in damage" because there are other life forms that have benefited so far from increased temperatures such as plants ... 

Also, how can you prove that your example isn't an isolated case ? I realize that some hot and inhospitable areas such as several patches of the sub-saharan desert and some middle eastern territories but for the most part much of Earth seems to be getting greener ... 

While Venus's case is extreme, the IPCC's pessimistic projection so far is 2 degrees celsius so you might want to cut your example by say a factor of 3 and do note that most of this warming will occur in colder regions rather than already hot regions like Australia as a consequence of the 2nd law of thermodynamics ... (Venus, I think in our entire solar system is the only planet of exhibiting a runaway greenhouse effect since Mercury which is even closer to the sun doesn't have a thick enough atmosphere to create the effect) 

China is already mostly done with it's industrial revolution according to the US BLS. They're soon going to be richer than both Turkey and Russia per capita since their economies aren't that advanced. The former's bet was to get into the EU single market and the latter's bet on oil but so far it hasn't worked out for both of them. The next likely industrial centers are going to be Africa and India since their still relatively unindustrialized ... 

As far as the risk of arctic regions releasing more emissions, most of the greenhouse gases aren't trapped at the arctic's surface. It's under the deep ocean where it's not likely to reach out of the water and is instead consumed by microbes ... 

As it stands, there are currently not strong enough factors to support a "climate change feedback" AKA "runaway greenhouse effect" like we see on Venus. Sure it'll get undeniably warmer but let's be rational and drop the fear mongering of entertaining the possibility of a rapid uncontrollable increase in temperature for reasons such as not receiving enough solar energy or having an extremely thick atmosphere ... 

There's not that much fossil fuel to be extracted from the arctic as far as past estimates suggest. It would maybe add a couple of years in our current reserves ? Really the biggest market for warming the arctic would be inhabitation in general ... 

We can sure synthesize biofuels but synthesizing shale or crude oil is simply too hard when geology gave these sources millions of years of optimization to compress the organic matter ... 

As far as you protesting Statoil, it is not in my place to comment on foreign nation's internal matters even though we share the same commonwealth realm. Whether you think the preservation of your local environment is more important than the welfare of your countrymen is yours to deal with ...  

A Snowball Earth, or at least strong glaciation similar to during the Ice Ages, is thought to have happened over 600 MA ago, but the circumstances for that were very special, as the landmasses all came together and formed the supercontinent Pannotia right above the south pole. In other words, the landmasses froze over - but the seas didn't fully freeze. What's interesting is what ended it even before Pannotia fully broke up: Once frozen Methane released when it started getting warmer, which caused additional warming and additional Methane getting released in a continuing circle, something that's also starting to happen right now.

Human-made global warming is a hoax. Forget those models from IPCC that are always wrong. They said back then there should be no ice in greenland during summer by 2014, but ice in greenland in breaking multi-decade record highs.

Actual data makes all IPCC computer models cringe.

I'm...reasonably confident the IPCC has never said that. They've been pretty consistently up front that predicting ice loss is extremely difficult, so I find it hard to believe they'd put forth a claim like that without heavily qualifying it. Do you have a source?

Also, I think you have the wrong type of "breaking." The ice sheets in Greenland are quite literally "breaking," as in, temperature is rising to the point where they're breaking apart.

The 2018 line of arctic sea ice thicknes, in black, compared to previous years. Actual data collected, not computer model.