It appears in a song sung by Ariel, to Ferdinand, a prince of Naples, after Ferdinand's father's apparent death by drowning: Full fathom five thy father lies, / Of his bones are coral made, / Those are pearls that were his eyes, / Nothing of him that doth fade, / but doth suffer a sea-change, / into something rich and strange, / Seanymphs hourly ring his knell, / Ding-dong. / Hark! now I hear them, ding-dong, bell. 2  All speeches are available online at www.bankofengland.co.uk/news/speeches  2  Long-term government bond yields have fallen sharply in tandem (Chart 2), with US 10-year yields their lowest in two and a half years, 10 year gilt yields their lowest since the immediate aftermath of the referendum, and German 10-year bund yields their lowest ever. $ trillion of global investment-grade debt is now trading at negative yields. Lower discount rates have provided substantial support to equity prices, which are near all-time highs in the US despite an economic outlook that is becoming less robust and more uncertain. Chart 2: Long-term bond yields sharply lower too 10-year nominal government bond yields Per cent 3.5 US  3.0 2.5 2.0  UK  1.5 1.0 Euro area  0.5 0.0 -0.5  Jul. 18  Oct. 18  Jan. 19  Apr. 19  Sources: Bloomberg Finance L.P., Tradeweb and Bank calculations. The global outlook These market developments reflect a sea change driven by growing concerns over the impact of rising trade tensions and policy uncertainty.
6  All speeches are available online at www.bankofengland.co.uk/news/speeches  6  Chart 6b: But households still optimistic about their own prospects Differences from averages since 1985 (number of standard deviations) 1.4 1.2 General economic situation expectations  1.0 0.8 0.6 0.4 0.2 0.0 -0.2 Personal financial situation expectations  -0.4 -0.6  Jan. 16  Jul. 16  Jan. 17  Jul. 17  Jan. 18  Jul. 18  Jan. 19  Sources: European Commission, University of Michigan consumer sentiment index, and Bank calculations. Notes: The chart shows the median across the G7 euro area countries (France, Germany and Italy) and the US. Reconciling market moves with global developments All in all, the risks to the global economy have shifted to the downside. But to what extent? Does the sea change in financial markets presage a sea change in the global economic outlook? And what does the UK experience suggest? A lot will rest on the scale and breadth of the trade effects. Traditional trade models suggest that the direct effects of the tariff measures implemented so far4 are likely to be small. The Bank estimates that these measures will reduce global GDP by only around 0.1%, and the further US-China tariffs that took effect in May and June will roughly double that effect (Table 1).5 But that may not be the end of the story.