There sure is a lot of doom and gloom concerning the outlook of humanity. It's at least partially shaping Christopher Nolan's vision of the future, with Interstellar at least partially addressing climate change and resource scarcity as primary drivers for space exploration. In the long run, space exploration as a solution will have to be addressed. In the short run, it's not a very practical answer. Any and all solutions need to be effected here, on Planet Earth. However, I'm pretty confident we can at least make it to when we can hop from planet to planet. Here's why:
We're Getting Smarter About It
Even as we argue among ourselves about climate change, the debate has at least kicked off serious efforts to do something about it. The truly appreciable effects are still a good ways into the future, but the baby steps are still helping. Increased public transportation infrastructure, smarter and more efficient means of personal transportation such as hybrid and electric cars, and serious interest in resource sustainability may be derided as little more than "feel good" window dressing, but it's that necessary first step. Moreover, it's indicating changing attitudes and intelligence about climate change and resource scarcity.
What's perhaps even more important than that, even, is addressing resource scarcity and pollution control without effecting or especially reducing quality of life for everyone. A high quality of life does not have to equate to "buying more stuff" and a better educated public is able to make wiser purchases. Technology is also aiding us too - with more efficient, resource-friendly products in more efficient, resource-friendly packaging, or going digital to forego physical packaging and transportation needs.
Of course, all that digit technology comes to naught if there's nothing to power it. This (along with food scarcity) is where the true threat of resource scarcity lies. Fortunately, we're getting smarter about that too. One of the unsung minor heroes of energy conservation is the gas turbine, a much more efficient and environmentally-friendly power source compared to the first coal-fired power generation plants. The gas turbine is obviously not a permanent solution (at least in fossil-fueled form), but it does show that technology can adapt and answer our resource scarcity needs.
In addition to stretching our fossil fuel dollar, we're getting more creative with where we get our power, period. The issue with solar power is finding an efficient means to capture it, and we are putting concentrated efforts into low-cost high-efficiency solutions with reduced environmental impact from their manufacture. Not everything has to be solar powered, either. Gas turbines (and diesel engines) can harness power from waste sources, such as landfills or sewage treatment plants. Such creative power solutions have a "double-whammy" effect of re-purposing pollution to solve resource scarcity.
At least individually, none of these solutions are an effective permanent panacea, but taken together, they buy us time to get our collective stuff together while ensuring we can power our laptops - and our heating and air conditioning too.
We're Getting Smarter About Populations, Too
The rising populations of India and China are particularly concerning as both nations rapidly increase their own industrialization. This results in a compounding problem - both nations have massive, growing populations couples with massive, growing manufacturing industries that consume resources larger than their already gargantuan proportions dictate, more than undoing the strides other nations with more mature industrial-tech bases and population growths have been making in resource management and pollution control. That's not to say that either nation is completely ignorant of these issues, or that they're not trying to do something about it.
The Chinese, in fact, are highly interested in pollution control. Their primary obstacle is in effecting means to achieve that. Their large populations and rapid industrial growth rate make it difficult, but China is essentially in the same position the United States was in the 1950s. Unlike that time, however, the Chinese do feel a vested interest in clean air and more efficient energy production in the middle of this development. Once again, it reflects changing attitudes as a result of the research and findings that have been discovered since the 50s, when societal awareness of environmental and resource issues was almost nonexistent.
Furthermore, the "population bomb" may be winding down. Industrialized nations across the board are reporting arrested or even shrinking population growth rates - which is also potentially troubling for future societies, but it at least eases fears and questions of how to sustain growing human populations. The mega-population numbers of India and China are often feared as more than offsetting this - but China's population growth is also slowing, and may be headed towards a crash, with or without the One Child Policy.
There's also some debate towards how much population the planet can sustain with optimistic but reasonable estimates saying 10 billion can be accommodated quite comfortably - a number that might not even be reached (if only barely) given slowed and contracting growth rates.
Every day, advancements are being made to increase the quality of life that can be achieved with less, and relieve the issue of resource scarcity. We're a pretty intelligence species, and we're pretty good at identifying problems and devising solutions. The issue of pollution-induced climate disasters and starving populations remains very real and relevant, and will continue to be for decades to come - but I'm hopefully optimistic that we can keep everything well and good until the point where we can colonize other worlds, and if it comes to that, get off the planet entirely (though I'm sure we're going to prove ourselves better caretakers of the one we got for now, too).