Esther Duflo, award Nobel Prize winner Economics in 2019, referred to economists in 2017 as plumbers of the system. We know that a pipe keeps working as long as the flow of entrance (which we can call the supply) is equal to the outflow (i.e. the demand), and that the pipe has no breakdowns that damage the equilibrium. Inflation, a phenomenon that economists are once again concerned about, can be understood as an excess of demand and a shortage of supply. For those of us who have not experienced the rigours of war, it is impossible to imagine a bigger plumbing problem than the one imposed by the pandemic over the last two years. When a pipe outlet becomes clogged (due to a demand shock), the water pressure tends to look for other drainage points. These diversions of economic resources reveal a picture of winners and losers.

In the worst months of the pandemic, the losses of traditional commerce were the gains of e-commerce and the losses of restaurants were the gains of food delivery. Some reinvented themselves effectively. While some restaurants closed, others developed their online services, including outsourcing their activity to the model de dark kitchen. Now, although their workers are not confined, it is just as important for a restaurant to fail its activities as it is to try to reinvent them when it cannot get the raw materials to prepare its dishes.

One example among many is the UK, which has suffered shortages of some products since the early 2020s. One of these was pasta: the supply chain starts mainly with Canadian wheat that is exported to Italy, where pasta is produced. The field, the factory, the sea and land transport: all these elbows and connections in the economic pipeline have been suffering some class of disruption. The reduction in production generated panic among British buyers, who hoarded pasta like American consumers once hoarded toilet paper.

Perhaps the biggest part of the supply shock is the increase in transport costs, caused in part by the lack of truck drivers in Europe and the UK, but above all by oil prices, which fell during the first stage of the pandemic and have recovered strongly with the boom in economic activity in recent months. On this point it is worth mentioning a shock unrelated to covid-19: the reduction in investment in the exploration and exploitation of oil wells. Banks and investment funds have pre-empted the government's emission reduction commitments with a decrease in their investments in fossil fuel exploitation. This leads to a limitation in the supply of these resources and is a factor in higher prices.

Despite the inflationary risk, it is necessary to reinvent ourselves towards a zero carbon society. But it is also important to bear in mind that every decision brings internal stress. Electric car batteries use lithium and Spain plans to get more than 70 billion euros from the European Recovery Fund to revive Economics and steer it towards greater sustainability. One of the proposed projects has been the opening of a lithium mine in Extremadura, with an investment of more than 1 billion euros, including a cathode and a cell factory. However, the project has been met with strong opposition from the local population because it is located very close to the city of Cáceres. This example illustrates how each solution has its cost and requires political will to reach an agreement with agreement in order to achieve the objectives set.

The pandemic has had a strong impact on supply and demand, reviving the phenomenon of inflation. Moreover, the high energy prices in 2021 are reminiscent of the inflationary episode triggered by the oil crisis of the early 1970s. The covid-19 crisis has also forced a reinvention of production systems, with a special approach focus on the supply chain. Duflo's analogy of the economist as plumber invites us to take off our ties and grab the spanner. It is an emergency because the pipe is leaking in several places but, above all, it calls for caution. As many have learned from their own experience, understanding how the pipe works before trying to fix it avoids ending up sitting in front of a good flood.