TOKYO (AFP) - Secretary of State Hillary Clinton launched her Asia tour in Japan Monday calling US-Pacific ties "indispensable" for curbing problems like climate change, the global financial crisis and nuclear weapons. The first chief US diplomat in half a century to start her diplomacy in Asia, Clinton arrived here amid warnings about a greenhouse gas timebomb in Siberia and Canada, a shrinking Japanese economy and North Korea's defiance over its nuclear programs and possible preparations for a missile launch. "I have chosen Asia on my first trip as secretary of state to convey that America's relationships across the Pacific are indispensable to addressing the challenges and seizing the opportunities of the 21st century," she said. Clinton was set to meet Japanese leaders on Tuesday and the following day travel on to Indonesia, followed by South Korea and finally China, a rising geopolitical and economic power with which the United States wants to partner. With historic ally Japan and new partners, "we can begin together to build networks around the world to help us solve problems that none of us can solve alone," she said after arriving at Tokyo's Haneda airport. In her talks with Japan's leaders and citizens, she said, "we will be looking for ways to collaborate on issues that go beyond just our mutual concerns to really addressing the global concerns." She said these would include "climate change and clean energy, Afghanistan, Pakistan, nuclear proliferation and other common concerns." It may be no accident Clinton first mentioned climate change, which she calls a national and global security threat. China is key to resolving the problem as it has overtaken the United States as the biggest greenhouse gas emitter. Over the weekend, new studies have warned of triggers in the natural environment, including a greenhouse-gas timebomb in Siberia and Canada that could viciously amplify global warming. Clinton omitted North Korea, a key topic for the three northeast Asian states she is visiting but one which analysts say should be discussed carefully behind the scenes for now as the new US administration reviews its policy. Analysts see Pyongyang's increasingly bellicose stance as a bid to keep its concerns on the international agenda as the new administration of President Barack Obama lists Afghanistan, Iraq, Iran and the Middle East as priorities. In Japan, meanwhile, the economics minister warned that Asia's biggest economy shrank at the fastest pace in 35 years in the fourth quarter and faces the worst crisis since World War II. Clinton said "the bilateral relationship between the US and Japan is a cornerstone in our efforts around world", adding that US and Tokyo needed to work together to address the global crisis. "The US-Japanese alliance is vitally important to both of our countries, to the Asia-Pacific region and to the world," she said. "And our partnership stretches back half a century, its foundation is based, and always will be, on a commitment to our shared security and prosperity." During her visit, Clinton was expected to arrange a date in March for US President Barack Obama and Japan's Prime Minister Taro Aso to meet for the first time, Japan's Jiji Press reported. Japan has greeted Clinton's visit as a sign that the Obama administration will maintain strong ties with the oldest US regional ally, despite China's ascendancy. "We will discuss ways to strengthen the Japan-US alliance. I think we will also strengthen our cooperation between Japan and the United States on the issue of North Korea," Japanese government spokesman Takeo Kawamura said. Clinton has agreed to meet families of the abductees, and said on the flight from Washington that their case is part of the six-party multilateral nuclear disarmament talks with North Korea. The six parties are the United States, the two Koreas, Japan, China and Russia. She was to hold talks with Japan's embattled leader, Aso, his foreign and defence ministers, and main opposition leader Ichiro Ozawa, whose party is leading in opinion polls ahead of elections later this year. Clinton also planned to sign an agreement to relocate 8,000 US marines from the southern Japanese base of Okinawa to the Pacific island of Guam. She will leave Japan on Wednesday and then visit Indonesia (February 18-19), South Korea (19-20) and China (20-22).