G19 versus USA on Paris Climate Agreement: Bold move, but will it make a dent on climate change?
Climate change became a major agenda in the G20 summit recognizing its close link to the global economy. In an almost unanimous decision, the G20 agreed that the Paris Agreement is “irreversible”.  This is in reaction to US President Donald Trump’s pullout from the Paris Agreement. German Chancellor Angela Merkel announced that it would make climate action a key focus of the G20 during its presidency. Germany further emphasized that ‘beyond the ratification of the Paris Agreement, G20 wishes to make headway on ambitious implementation and to support third countries in doing so.’ 
G20 is a self-designated premier forum for international economic cooperation composed of governments and central bank governors from the world’s 20 major economies. Initially formed in 1999, its first heads of state summit was held after the 2008 financial crash, purportedly to provide a broader and more inclusive institution than the G7 group of rich states.  Member countries include Argentina, Brazil, Canada, China, India, Turkey, and several European Union countries as well as the EU being a member itself.
However, G20 is nowhere near meeting its objectives. Economic growth in big capitalist countries barely exceeded 2% per year since 2010, after contracting in 2008-2009.  Further, their carbon intensive framework for global economic development continues to aggravate social, economic and environmental crisis affecting the world’s poor and the planet. Together, they contribute nearly 80% of GHG (Greenhouse Gas Emissions) in the atmosphere causing global warming and climate change, but total contribution to reduce their emissions is by far insufficient.
The United States withdrawing from a climate policy is nothing new. Not only because Trump’s denial of the science of climate change has been consistent since his election, but also worth highlighting is that past US Presidents never stepped up to its responsibilities to climate change.
The United States has a long-standing history of diluting and road-blocking any global climate action. It is the biggest historical polluter in the world, thus it has the biggest accountability to the climate crisis. While it has consistently been the world’s second largest emitter since the industrial revolution, its emissions grew 266 times larger in recent years than those in 1850.  Its 1850 emissions were at 19.79 MtCO2 and swelled to 5,256.99 MtCO2 in 2011. Despite Barack Obama’s signature for the Paris Agreement, its actual pledge was only a fifth of its fair share. 
The United States also showed no interest to the previous climate agreement, the Kyoto Protocol.  Before George W. Bush withdrew from the Kyoto Protocol, the United States ensured exemptions from emission limits on bunker fuels and all military operations worldwide—including war.
While not being talked about in any climate negotiations, the US military operations consume fossil fuels beyond compare to any other institutional and per capita consumption in the world. Its projected full cost of the Iraq war is estimated to cover "all of the global investments in renewable power generation" needed between now and 2030 to reverse global warming trends.  Yet it remained untouchable to any