We　present　a　new　approach　to　estimate　time　variations　in　J2.　Those　variations　are　represented　as　the　sum　of　contributions　from　individual　sources.　This　approach　uses　solely　Gravity　Recovery　And　Climate　Experiment　(GRACE)　data　and　the　geoid　fingerprints　of　mass　redistributions　that　take　place　both　at　the　surface　and　in　the　interior　of　the　solid　Earth.　The　results　agree　remarkably　well　with　those　based　on　satellite　laser　ranging,　while　estimates　of　the　sources　explain　the　observed　variations　in　J2.　Seasonal　variations　are　dominated　by　terrestrial　water　storage　and　by　mass　redistribution　in　the　atmosphere　and　ocean.　Trends,　however,　are　primarily　controlled　by　the　Greenland　and　Antarctic　ice　sheets　and　by　glacial　isostatic　adjustment.　The　positive　trend　from　surface　mass　variations　is　larger　than　the　negative　trend　due　to　glacial　isostatic　adjustment　and　leads　to　an　overall　rising　trend　during　the　GRACE　period　(2002–2017).　©2019.　The　Authors.