Back in 2018, the German Chancellor announced she would stand down as leader of the CDU at the party convention. She said she would not seek a fifth term as Germany takes to the election polls this year.
In January, Armin Laschet was announced as the new leader of the CDU party after beating rival Friedrich Merz in a digital leadership election.
But Mr Laschet has faced mounting scrutiny over past statements defending Russian President Vladimir Putin and the Assad regime in Syria.
But Ms Adler has issued a different warning to Ms Merkel as a recent poll found Germany’s Green Party could win the election for the first time in its 41-year history.
In a comment piece on the BBC, Ms Adler said: “Crucially for German voters, the Green candidate for chancellor, Annalena Baerbock, is a centrist member of her party.
“What Germans call a Realo (respecting realpolitik) rather than a Fundi (fundamentalist).
“There’s a good chance Annalena Baerbock could woo the female vote too.
“Or at least a good chunk of it.
“Women made up 52% of support for Merkel’s conservative party in the last federal election.”
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The study by Forsa showed 28 percent of respondents backing the Greens as the most popular party.
Support for Mrs Merkel’s centre-right CDU/CSU bloc slumped with just 21 percent backing it to form the next government.
It represents a six-point drop in approval for the governing party, which has been widely criticised for the sluggish rollout of coronavirus vaccines across Germany.
Just 13 percent said they would back the centre-left Social Democratic Party, a senior member of the current ruling coalition.
This is not the first time Ms Merkel and her party have been warned they could face a tough election race this year.
Ms Merkel was warned thousands would leave the party after Mr Lachet was announced as the new leader.
Christian von Stetten, the chairman of the Mittelstand parliamentary group (PKM) of the Union faction warned many party members have toyed the idea of leaving.
He said: “If Merz is not involved at the top, we are not talking about hundreds of exits, but thousands.”
