Mexico’s left-leaning climate scientist Claudia Sheinbaum secured enough votes to become the Latin American country’s first-ever female president.

The country’s electoral institute published a rapid count estimate late Sunday night saying that Sheinbaum had won the presidential election. The estimate has a margin of error of +/-1.5%, the institute said.

In the landmark vote, Sheinbaum defeated her election rival, center-right businesswoman Xóchitl Gálvez, after dominating in the polls for months.

A protégé of her long-time ally and mentor Andrés Manuel López Obrador, Sheinbaum is now poised to succeed AMLO when his six-year term as president comes to an end on October 1.

Sheinbaum, a former Mexico City mayor who was dubbed the “ice lady” by her political rivals, has pledged to largely continue with AMLO’s policies and has received the backing of his ruling Morena party.

Sheinbaum has previously worked as a contributing author to a report from the U.N.’s Intergovernmental Panel on Climate Change. Yet, the 61-year-old did not make the climate threats facing Mexico a central part of her campaign.

Analysts have said Mexico’s next government will face significant fiscal and structural realities that are likely to lead to tough choices when it comes to balancing investment plans, the popular yet costly welfare programs and, perhaps most importantly, state petroleum company Pemex.

“Without a concrete solution to the elephant in the room — Pemex — neither external market sentiment nor the credit ratings agencies are convinced of Sheinbaum’s fiscal credentials,” analysts at Verisk Maplecroft said in a recent research note.

“Her main proposal — to kick the can down the road by refinancing Pemex’s upcoming debt obligations (USD 6.8 billion in 2025, followed by USD 10.5 billion in 2026 — and a total of USD 39 billion by the end of the decade) — are unlikely to wash with investors, given Pemex’s deep structural issues,” they added.