Enterprises are at the forefront of climate actions and multinational enterprises (MNEs) engage in foreign direct investment (FDI), allowing them significant influence over the entire supply chain.Yet emissions embodied in MNEs international supply chains are poorly known. Here we trace the carbon footprints of MNEs foreign affiliates and show the gross volume of global carbon transfer through investment peaked in 2011, mainly driven by the decline in carbon intensity. Despite declining carbon footprints of developed country-based MNEs, there has been a significant increase in carbon transfer sourced from the Chinese mainland. We propose an investment-based accounting framework to allocate carbon footprints of MNEs to the investing country. Investment-based accounting of emissions could inform targeted and effective climate policies and actions. For instance, some large MNEs play a crucial role in carbon transfer, therefore their originating country should bear more responsibilities of carbon emission reduction as an investor. [143 words] In 2015, the Paris Agreement set the target of holding this century's global warming well below 2°44 C above pre-industrial levels. However, the sum of current national pledges and companies' commitments to climate mitigation falls short of meeting the Paris goal 1-3 . Global climate change mitigation calls for more active actions from governments, businesses and investors 4 . Currently, enterprises -particularly MNEs 5-7 -are at the forefront of climate action. For instance, thousands of US businesses have declared that they will continue to support climate action and work towards meeting the terms of the Paris Agreement 8 , despite President Trump's announcement that the US will withdraw from the Agreement. Carbon footprint measurement is the first step in reducing carbon emissions 9 . However, the global reach of MNEs makes it more difficult to measure their carbon footprints, especially the carbon footprint of their foreign affiliates, which is also a popular topic of current research 5 . This study attempts to enrich the related literature in the following ways.Here we present a comprehensive study to trace carbon emissions embodied in the supply chains of global MNEs. Existing studies mainly assessed the carbon footprints of MNEs originating in or hosted by a particular country in a certain year, such as China 10-12 or the US 5 . For instance, López et al. (2019) 5 found that in 2009 the carbon footprint of US MNEs' foreign affiliates was greater than that of the territorial emissions of the UK. Different economies around the world may play different roles in global investment networks, which have also been changing over recent years.This study extends the literature by providing time-series and global-level analysis of the carbon footprints of MNEs. We provide two methods, the decomposition method and the hypothetical extraction method (HEM) 13 , to calculate the carbon footprints of MNEs and prove that these two methods share the same results 14 . The results of these ca...