Getting that commitment involved a two-year campaign during which they staged a "marriage" between the 900-year-old university and "Big Oil" before breaking it up, to symbolise the need to end investment in fossil fuels, Micklewaite said.
"The campaign is definitely going to continue," she told Reuters, adding that full divestment is her aim for the 3.8 billion pounds ($6 billion) in university endowment funds.
The second-year engineering student from Balliol College is not alone. She is part of a global campaign urging investors to ditch assets in 'dirty' energy firms in favour of 'greener' rivals, and which so far has pledges to sell out totalling $50 billion.
Norway's $900 billion sovereign wealth fund and the Church of England are among recent high-profile sellers.
But some of the money managers running the more than $27 trillion in assets held globally in mutual funds say divestment as a tool to address climate change is too simplistic in most cases. Most argue it can leave fewer investors at a company who are committed to steering management in the desired direction.
"It's a much more sophisticated debate," said Sacha Sadan, director of corporate governance at Legal & General Investment Management. "Just putting (some firms) in the naughty corner and having a go at them is not going to solve the problem."
"This will be the biggest issue of the next five years ... I wouldn't say that we're 20 percent of the way there yet."
A Reuters survey of nine European fund firms managing a collective $2.7 trillion in assets revealed that most were focused on engagement with companies rather than divesting.
That approach bore fruit during recent annual general meetings, where shareholders at Royal Dutch Shell and BP demanded access to information about how each company was addressing climate change, and received company backing for their resolutions.
And in the United States, shareholders at Chevron and ExxonMobil are due to vote on May 27 on resolutions aimed at reducing greenhouse gas emissions.
Each of the fund firms surveyed acknowledged the campaign's role in raising awareness, but most said coal and tar companies were relatively easy targets, and it was more complex for other energy sources.
"What's much harder, with the integrated oil and gas companies, from a mainstream fund perspective, is what models can you develop and put in place to determine who will be impacted by the energy transition," said Matthias Beer, from the sustainable investing team at F&C Asset Management.
"That goes beyond oil and gas and mining and utilities. If you go further down the value-chain of fossil fuels, then you're talking about the automotive sector and others that are highly dependent on fossil fuels and hydrocarbons."
Oxford University joins 220 organisations, including faith groups and university endowment and public pension funds, in backing divestment ahead of a U.N. climate change meeting in Paris in December aimed at agreeing limits to man-made global warming.
The U.N. talks could add weight to the campaign if a deal ultimately means billions of dollars worth of oil, coal and gas resources remain 'stranded' in the ground.
For Jens Peers, chief investment officer for sustainable equities at Natixis Asset Management, the PR effect is key.
"Already, we're seeing pressure building. No one likes negative press," said Peers.
That in turn is pushing investors to seek advice, said Fiona Reynolds of U.N.-backed investor engagement group the Principles for Responsible Investing.
"This is where the divestment campaign has been successful, even if the actual amount of money that has been divested is pretty minor," Reynolds told Reuters.
But an Oxford University study in late 2013 argued the indirect impacts of divestment campaigns on companies could be wide-reaching, with those seen as worst offenders "stigmatised".
This could result in a hit to the bottom line as investors trimmed cash flow expectations and share valuations, it said.
Other potential impacts highlighted by the report include customers and other stakeholders deserting firms; politicians enacting more restrictive legislation; investors pushing for board changes and even firms being prevented by authorities from bidding for new business or having M&A deals scuttled.
"Then they will start reacting, questioning the business model - that's potentially the biggest impact the divestment and stranded asset issues can have," said Natixis AM's Peers.
The Oxford study cited the examples of a campaign to force South Africa to abandon apartheid and one to divest from tobacco firms. In the case of South Africa, for example, the U.S. government enacted the 1986 Anti-Apartheid Act, it said, while the Bank of Boston, Chase Manhattan and Barclays were among companies to stop doing business in the country.
The funds surveyed by Reuters said leading energy companies had a crucial role to play in finding technological solutions to mitigate climate change risks, with early movers likely to be rewarded in terms of access to capital and share price gains.
Simon Henry, chief financial officer at Shell, said the industry needed to work with governments and civil society on a long-term plan informed by science and economics and mindful that 80 percent of the energy industry and 100 percent of the transport sector is currently reliant on fossil fuels.
Given that, a mass exodus of long-term investors such as pension funds from holding certain stock and debt assets could end up hurting the chance of positive investor-led change.
"Fundamentally, it is a shareholder choice to buy or sell ... What this may mean is the transfer away from shareholders who might have a grown-up dialogue with us about the climate change challenge towards people who may be less bothered about that.
($1 = 0.6379 pounds)
(Additional reporting by Nina Chestney in London; Editing by Alexander Smith and Pravin Char)
By Simon Jessop and Ron Bousso