This meta-analysis of over 2,400 papers tracks the influence of older publications that have 'echoed' through the decades, cited in countless publications and creating a potentially false confirmation bias.
Echo chambers in science describe the amplification and repetition of information within closed networks. Frequently used data sources can cause echo chambers as scientists keep reading similar outputs from different sources, creating false perceptions of certainty and variety of data sources. We show this effect by studying the scientific and grey literature on water use by electricity systems. The power sector is the largest contributor to anthropogenic carbon emissions and the second largest water consumer. We have assessed the scope and references of 2,426 papers and created a citation network to trace original data sources. Most data sources used for the last 30 years originate from a few old US publications, recently also Chinese, that echo through publications. This echo effect, also reflected in recent scientific publications, creates a confirmation bias, also facilitating double counting of the water intensities of electricity generation. This example from sustainability science warns of the risk of echo chambers in other scientific disciplines.