The rise of climate discourse on social media offers new channels for public engagement but also amplifies mis- and disinformation. As online platforms increasingly shape public understanding of science, tools that ground claims in trustworthy, peer-reviewed evidence are necessary. The new 2026 iteration of ClimateCheck builds on the results and insights from the 2025 iteration (run at SDP 2025/ACL 2025), extending it by adding training data, a new task on classifying disinformation narratives in climate discourse, and a focus on sustainable solutions.

The ClimateCheck shared task is a part of the the 3rd International Workshop on Natural Scientific Language Processing (NSLP 2026), which will take place on May 12 2026 and is co-located with LREC 2026 in Palma de Mallorca (Spain).

***Available Tasks*** Task 1: Abstract retrieval and claim verification: given a claim and a corpus of publications, retrieve the top 5 most relevant abstracts and classify each claim-abstract pair as supports, refutes, or not enough information. Evaluation: Recall@K (K=2, 5) and B-Pref (for retrieval) + Weighted F1 (for verification) based on gold data; additional unannotated documents will be evaluated automatically. In addition, we will ask participants to use CodeCarbon to assess emissions and energy consumption at test inference.

Task 2: Disinformation narrative classification: given a claim, predict which climate disinformation narrative exists according to a predefined taxonomy. Evaluation: Macro-, micro-, and weighted-F1 scores based on annotated documents.

***Important Dates*** - Release of datasets: December 15, 2025 (task 1); December 19, 2025 (task 2) -) Both datasets are now available for training! - Testing phase begins: January 15, 2026 (Codabench link TBA) - Deadline for system submissions: February 16, 2026 - Deadline for paper submissions: February 20, 2026 - Notification of acceptance: March 13, 2026 - Camera-ready papers due: March 30, 2026 - Workshop: May 12, 2026

We encourage and invite participation from junior researchers and students from diverse backgrounds. Participants are also highly encouraged to submit a paper describing their systems to the NSLP 2026 workshop.

***Call for Participation*** The call for participation with more information can be found here: https://nfdi4ds.github.io/nslp2026/