Europe's greenhouse gas emissions rebounded in 2021 due to the post-pandemic recovery and the continent must step up efforts if it hopes to meet its targets, the European Environment Agency (EEA) warned Wednesday.

Preliminary data reported by EU member states showed that greenhouse gas emissions rose by five percent in 2021 from 2020, mainly due to the post-Covid economic recovery, a new EEA report showed.

The emissions remain nonetheless six percent below the 2019 pre-pandemic level.

The EU target of a 55-percent reduction in net emissions by 2030 "is not expected to be reached according to current projections", agency expert Melanie Sporer told reporters.

"We will need to double our efforts on greenhouse gas emissions every year from 2021 to 2030, compared to 1990 to 2020, in order to reach the different targets", she said.

The biggest efforts were noted in the field of energy supply, the industry with the highest emissions, the EEA noted.

The sector's emissions declined by 43 percent from 2005 to 2020, while they dropped by 15 percent in the transport industry and two percent in the agriculture sector.

The total share of renewable energies in energy consumption remained stable in Europe at 22 percent following several years of sharp expansion -- a source of concern at a time when the transition to green energy needs to be accelerated.

The EEA said wind and hydro power needed to rapidly increase, by about 2.5 percent annually, to reach the target of 45 percent of renewables by 2030.