Concerns about the pitiful prospects for millions of people in the UK currently in workplace defined contribution pension schemes is well founded. It should lead trustees and others with responsibility for investment decisions to focus on working assets harder. This should not mean turning over portfolios evermore frequently – it should mean attentive stewardship of companies in pension portfolios based on analysis of the full range of risks that may inhibit returns over the short, medium and long term.The long term is, of course, what counts for most pension savers. To protect the interests of younger savers in particular, there’s a compelling case for fiduciaries to engage with the long-term economic implications of climate change. Lord Stern, the former World Bank chief economist who undertook a rigorous cost-benefit analysis of ignoring climate change, found that “the overall costs and risks of [inaction on] climate change will be equivalent to losing at least 5% of global GDP each year, now and forever”. He adds: “If a wider range of risks and impacts is taken into account, the estimates of damage could rise to 20% of GDP or more. In contrast, the costs of action – reducing greenhouse gas emissions to avoid the worst impacts of climate change – can be limited to approximately 1% of global GDP each year.”Any prudent trustee with responsibility for the retirement savings of people under 45 years of age should be paying close attention to avoiding the potentially devastating impact of climate change on fund valuations in the decades to come. The low-carbon transition our economies must inevitably undergo will not be without some short-term pain, particularly for investors with heavy exposure to high-carbon sectors. Responsible fiduciaries have no choice but to grapple with these challenges. It is hugely encouraging Europe’s pension funds are now doing so.Catherine Howarth is chief executive at ShareAction Catherine Howarth, chief executive at ShareAction, says pension funds have no choice but to grapple with the issue of climate changeIPE deputy editor Daniel Ben-Ami is absolutely right to argue, as he does in his recent comment piece, Keep Politics Out of Pensions, that pension funds’ investment decisions should avoid political bias. The courts have ruled that trustees are barred from bringing their own political or ethical views, however strongly held or well intentioned, into decisions made as fiduciaries of other people’s money. There can be one, and only one, consideration for those who make investment calls with others’ retirement savings: the best interests of the saver.This requirement to secure savers’ best interests, which entails a strong though not exclusive focus on financial interests, is exactly why high-performing pension funds in the UK and across Europe have embraced responsible investment in recent years. The terminology of ‘environmental, social and governance’ (ESG) may be somewhat clumsy, but the wide variety of considerations that fall under that umbrella are demonstrably material to savers’ financial security and quality of life in retirement.Research undertaken by Arabesque Partners in association with Oxford University, published last year, assessed 200 of the highest-quality academic studies examining the economic evidence for sustainability. This showed that 90% of studies find that sound sustainability practices lower companies’ cost of capital, and 88% of studies show that strong ESG performance drives better operational performance by companies. Even when focusing on shareprice performance, 80% of studies find a positive correlation between good sustainability practices and strong share price performance.