Everyone wants clean environment to live in. New technologies, education & governmental incentives & legislation can help to curb pollution of carbon dioxide, plastics, smog, toxins, etc. Banning the sale of cars run solely on fossils fuels by 2040 is an example of governmental incentives & legislation to curb pollution.
About half of all fossil fuels had been burnt since the industrial revolution & has given raise nearly a degree centigrade rise in global temperatures. Thus if the rest of fossil fuels are burnt a total of about 2 degree centigrade rise will be likely. Hotter air can cause extreme climate. Global warming of around 2 degrees centigrade will cause increased coastal flooding, as well as more drought & famine - turning agricultural land into desert (in an era of exponential population rises).
Apparently, UK experimental SABRE (Synergistic Air-Breathing Rocket Engine) ram jet engine is capable of single-stage-to-orbit capability at over Mach 5.2 (3,800 mph). SABRE engines burns hydrogen with atmospheric oxygen and when the space plane reaches an altitude of around 16 miles and five times the speed of sound (i.e. Mach 5), it switches to its onboard liquid oxygen tank to reach orbit. Being in orbit, such a craft can travel in opposite direction to the rotation of the earth thus saving energy & time of travel.
For example,
http://www.telegraph.co.uk/news/science/science-news/9709041/Britain-to-Australia-in-four-hours-with-new-engine.html confirms that using space plane travelling between UK to Australia could take around 4 hours.