Hansen et al (2013) explores how the world can avoid anthropogenic global warming of (much) higher than 2°C in the next few centuries. The scenario that allows the maximum level of slacking off is to continue greenhouse gas emissions at present levels until the 2040s, then cutting 5% of emissions every year thereafter.
Simulated global temperature (Fig. 9) is for CO2 scenarios of Fig. 5. Peak global warming is ~1.1°C, declining to less than 1°C by mid-century, if CO2 emissions are reduced 6%/year beginning in 2013. In contrast, warming reaches 1.5°C and stays above 1°C until after 2400 if emissions continue to increase until 2030, even though fossil fuel emissions are phased out rapidly (5%/year) after 2030 and 100 GtC reforestation occurs during 2030–2080. If emissions continue to increase until 2050, simulated warming exceeds 2°C well into the 22nd century.
So. Good luck with that, all countries of the world.
The paper has a lot of material to chew on and digest. For instance, here's a a pie chart on who's helped caused greenhouse gas emissions for the last 2.5 centuries of industrial civilization.
Here's the most optimistic/realistic section of text:
Our analysis shows that a set of actions exists with a good chance of averting "dangerous" climate change, if the actions begin now. However, we also show that time is running out. Unless a human "tipping point" is reached soon, with implementation of effective policy actions, large irreversible climate changes will become unavoidable. Our parent's generation did not know that their energy use would harm future generations and other life on the planet. If we do not change our course, we can only pretend that we did not know.