Taxes may have to be raised to pay for benefits for older people if Scotland gets new controls over welfare, a report has warned.
Economics expert Professor David Bell said consistent economic growth would be needed to pay for benefits for older people "if increases in the tax burden are to be avoided".
Prof Bell issued the warning in a new paper looking at spending on welfare in Scotland. He will also address the issue in a seminar organised by the David Hume Institute think tank in Edinburgh.
In his paper, the Stirling University professor said: "If Scotland acquires new fiscal responsibilities, including control over welfare benefits, there will be a need to raise revenues to meet the increased costs of state pensions. These will have to be derived from the economic activity of the working-age population."
While he said retirement ages were to increase gradually over the next 20 years, he added: "Nevertheless, meeting the costs of welfare entitlements for older people will require a return to consistent patterns of economic growth if increases in the tax burden are to be avoided."
Prof Bell said the number of pensioners in Scotland is expected to increase by 80% between 2010 and 2060. In 2010-11 Department for Work and Pensions payments on welfare and state pensions in Scotland totalled £15.6 billion, with councils spending a further £5.2 billion on support for groups such as older people, children and the homeless.
Overall spending on "social protection" - welfare benefits and state pensions - was higher in Scotland than the UK as whole, at £3,972 per head of population compared with £3,658 for the UK.
Prof Bell explained that higher spending north of the border was "largely driven by having a higher share of pensioners and disabled people in the population". He said no clear, costed vision of a welfare system in Scotland under either independence or an enhanced devolution settlement had yet been set out.
He argued the political costs of bringing in means-testing for universal benefits - such as concessionary travel for the elderly - were "likely to be higher" than introducing a tougher assessment on benefits that are already means-tested.
Prof Bell said benefit payments played "a vital role in supporting the incomes of types of household" - such as pensioners - who often have "limited alternative sources of income". This, he added, showed the difficulties "that a Scottish Parliament with enhanced powers would have in making significant alterations to the existing structure of welfare benefits".