By Emily Kaiser
SEOUL, Nov 10 (Reuters) - The Group of 20 rich and emerging economies came together at the height of the financial crisis in 2008 to try to prevent a global recession from becoming a depression.
Its coordinated efforts are credited with short-circuiting the financial panic and restoring economic growth, albeit still sluggish in many regions.
Here is a look at the first four leaders' summits and what is left to be done at the fifth in Seoul this week.
WASHINGTON, NOVEMBER 2008:
The first summit came just two months after the collapse of Lehman Brothers triggered a meltdown that brought the world's financial system to the brink of collapse. Talk was rampant of a Great Depression 2.0.
Global trade had dropped off a cliff as financing dried up, spreading the economic pain to exporting countries that had managed to avoid the banking crisis. U.S. and European officials were scrambling to bail out financial firms at risk of failure and guarantee savers' deposits.
The main accomplishment of this meeting was simply getting everyone in the same room. It was a tacit acknowledgment that the G7 club of rich countries could not solve this problem alone, and needed to get emerging markets on board.
Leaders pledged to work together to restore growth and create a financial regulatory structure that was strong enough to prevent a repeat of the crisis.
LONDON, APRIL 2009:
In the five months between the Washington and London summits, global stock markets tanked and investors questioned the solvency of some of the biggest banks. The Dow Jones Global Titans index of the largest companies fell 14 percent.
Calling this the "greatest challenge to the world economy in modern times" the G20 said it would do whatever it took to arrest the economic free-fall.
The centrepiece was tripling the International Monetary Fund's resources so that it could support emerging and developing economies caught in the downdraft.
U.S. President Barack Obama received a rock star's welcome, and even met with Queen Elizabeth.
PITTSBURGH, SEPTEMBER 2009:
A year after Lehman Brothers, leaders could breathe a bit easier knowing they had averted a depression. Indeed, they felt so confident of their success that they declared in their closing statement: "It worked."
The focal point was the "Framework for Strong, Sustainable and Balanced Growth," which was a commitment to adopt domestic policies that would foster healthier global growth less prone to the booms and busts that marked the last decade.
The idea was that exporting powerhouses such as China and Germany would act to bolster domestic demand, while the borrow-and-spend countries such as the United States and Britain would embrace savings and investment.
As part of this U.S.-led push for rebalancing, each country submitted medium-term economic plans for IMF review of whether they were mutually compatible.
TORONTO, JUNE 2010:
The first signs of fractures were clearly visible in Toronto as a synchronized global recession gave way to a multi-speed recovery.
Greece's debt troubles turned attention on the precarious state of some European governments' finances and cast doubt on the very survival of the euro zone.
Germany led a drive toward austerity, arguing that healthy government finances would foster confidence and that in turn would drive stronger economic growth.
The United States saw dangerous parallels with 1937, when its own government abruptly cut spending thinking the recession was over. Instead, the cutbacks prolonged the depression.
Papering over their differences, the G20 agreed to halve deficits by 2013, which sounded bold but in reality was nothing beyond what governments -- including the United States -- had already promised. That pledge exempted Japan, which carries the largest government debt burden as a percentage of GDP.
The IMF told leaders that if they adopted complementary domestic economic policies, global output could be $4 trillion higher in the medium term than if they go their separate ways.
SEOUL, NOVEMBER 2010:
Divisions have deepened as the pace of recovery diverges. The United States, Europe and Japan appear stuck in neutral while emerging markets charge ahead.
This was supposed to be the culmination of two years of G20 cooperation, marking the end of crisis and the beginning of a new era of shared growth.
Although leaders are expected to endorse a deepening of the "framework" first agreed in Pittsburgh, the frictions are unmistakable.
Currencies have moved to the centre. A weak U.S. dollar, a consequence of slow growth and the Federal Reserve's easy money policy, has sent investors into higher-yielding markets, raising the risk of asset bubbles and inflation.
Regulatory reform remains unfinished. Although leaders will most likely approve "Basel III" reforms of bank capital rules, they have yet to figure out how to safely shut down large, international firms in danger of collapsing.
Leaders will no doubt put on a show of unity this week, heralding accomplishments such as extending the "Framework" and promising to avoid competitive currency devaluations.
Unless they can defuse the growing tensions, however, questions will remain about whether this group that could shine in crisis is now too unwieldy and diverse to effectively safeguard the recovery. (Editing by Tomasz Janowski)