Currently the global GHG emissions are about 50 giga tons of CO2 equivalent (GtCO2eq).
With business as usual scenario, this will rise to 110 GtCO2eq by 2050.
With the pledges made at COP21 in December 2015 in Paris, the emissions will stay flat at around 50 GtCO2eq until 2050 and then start declining after 2050.
Source: http://www.irena.org/rethinking/IRENA%20_REthinking_Energy_2nd_report_2015.pdf