Australia's Prime Minister Malcolm Turnbull attends the opening ceremony of the G20 Summit in Hangzhou on September 4, 2016. G20 leaders confront a sluggish global economy and the winds of populism as they open annual talks, but the long war in Syria and the South China Sea territorial dispute hang over the summit. / AFP PHOTO / POOL / Mark SchiefelbeinMARK SCHIEFELBEIN/AFP/Getty Images

Saudi Arabian Deputy Crown Prince Mohammed bin Salman (R) attends the opening ceremony of the G20 Summit in Hangzhou on September 4, 2016. G20 leaders confront a sluggish global economy and the winds of populism as they open annual talks, but the long war in Syria and the South China Sea territorial dispute hang over the summit. / AFP PHOTO / POOL / Mark SchiefelbeinMARK SCHIEFELBEIN/AFP/Getty Images

German Chancellor Angela Merkel (L) and U.S. President Barack Obama (R) talk before the start of the opening ceremony of the G20 Summit in Hangzhou on September 4, 2016. G20 leaders confront a sluggish global economy and the winds of populism as they open annual talks, but the long war in Syria and the South China Sea territorial dispute hang over the summit. / AFP PHOTO / POOL / Mark SchiefelbeinMARK SCHIEFELBEIN/AFP/Getty Images

US President Barack Obama smiles during the opening ceremony of the G20 Summit in Hangzhou on September 4, 2016. G20 leaders confront a sluggish global economy and the winds of populism as they open annual talks, but the long war in Syria and the South China Sea territorial dispute hang over the summit. / AFP PHOTO / POOL / Mark SchiefelbeinMARK SCHIEFELBEIN/AFP/Getty Images

Argentina's President Mauricio Macri (R) attends the opening ceremony of the G20 Summit in Hangzhou on September 4, 2016. G20 leaders confront a sluggish global economy and the winds of populism as they open annual talks, but the long war in Syria and the South China Sea territorial dispute hang over the summit. / AFP PHOTO / POOL / Mark SchiefelbeinMARK SCHIEFELBEIN/AFP/Getty Images

Thailand's Prime Minister Prayut Chan-O-Cha (L) arrives for the G20 Summit in Hangzhou on September 4, 2016. G20 leaders confront a sluggish global economy and the winds of populism as they open annual talks, but the long war in Syria and the South China Sea territorial dispute hang over the summit. / AFP PHOTO / POOL / Rolex DELA PENAROLEX DELA PENA/AFP/Getty Images

Spanish Prime Minister Mariano Rajoy (R) arrives for the G20 Summit at the International Expo Center in Hangzhou on September 4, 2016. G20 leaders confront a sluggish global economy and the winds of populism as they open annual talks, but the long war in Syria and the South China Sea territorial dispute hang over the summit. / AFP PHOTO / POOL / Rolex DELA PENAROLEX DELA PENA/AFP/Getty Images

Thailand's Prime Minister Prayut Chan-O-Cha (L) arrives for the G20 Summit at the International Expo Center in Hangzhou on September 4, 2016. G20 leaders confront a sluggish global economy and the winds of populism as they open annual talks, but the long war in Syria and the South China Sea territorial dispute hang over the summit. / AFP PHOTO / POOL / Rolex DELA PENAROLEX DELA PENA/AFP/Getty Images