Data Scientist

Personio GmbH; Greater London; Hybrid; GBP 60,000 - 75,000; Full time

Job summary

A non-profit organization focused on climate data in London is seeking a Data Scientist. The role involves analyzing datasets, developing and deploying NLP models, and collaborating with climate experts and software engineers. A hybrid work environment with a 4-day workweek is offered. Ideal candidates have 3-5 years of experience in applied NLP, excellent Python coding skills, and are enthusiastic about climate change and innovation.

Benefits

Unlimited annual leave

Wellbeing allowance

4 day workweek

Qualifications

• 3–5 years of experience tackling applied NLP problems with machine learning.
• Demonstrated ability to move ideas from proof-of-concept to working implementations.
• Excellent ability to write well-tested, maintainable Python code.

Responsibilities

• Work closely with the existing team to analyse datasets.
• Develop, evaluate, and deploy state-of-the-art NLP models.
• Contribute to building evaluation harnesses for search relevance.

Skills

Applied NLP

Machine Learning

Python programming

Data analysis

Collaboration

Tools

PyTorch

Spacy

Pandas

AWS

PostgreSQL

FastAPI

Job description

Data Scientist

Permanent employee, Full-time · London Hybrid - 4 Day Work Week

Salary: £60,000 – £75,000 per year

About us

Climate Policy Radar is a non-profit organisation building open databases and research tools so people can discover and understand complex information on climate, nature and development. Our data and tools help governments, researchers, international organisations, civil society, and the private sector to understand and advance effective climate policies and deploy climate finance. Harnessing data science and AI, and pioneering the application of natural language processing to this domain, our work renders previously unstructured, siloed data more readable and accessible.

We are a team of ~30 technologists and climate policy experts who care about the ‘how’ (values and culture) as well as the ‘what’. We have embraced a flexible, hybrid approach to work, including a 4 day workweek. We are looking for a Data Scientist to join our data science team.

Roles and responsibilities

This is a growth hire, adding to climate Policy Radar’s data science capacity. Reporting to the Head of Data Science, you will work closely with the existing team to analyse datasets, build tools to deepen analysis, and productionise those tools for users to leverage in their research.

As a skilled generalist within NLP, you’ll work on a range of problems, collaborating with climate experts to understand the problems to solve and with software engineers to take work from research through to production.

About the data science team

Climate Policy Radar's engineering organization is split into functional teams: programmes (domain experts), platform (high-quality data sharing), application (user-facing tools), and data science (models and evaluation). Our work is cross-functional; we publish datasets, models, and papers where we can, and share learnings through blogs, papers, and public talks.

The data science team builds models powering our search engine, classifiers, and LLM workflows, with evaluation frameworks to keep them honest. Our work informs policy decisions, so we care about evaluation, monitoring, and minimising bias. We are research-informed but production-focused, and we default to working in the open.

Tech preferences

The vast majority of the data science team’s work is written in Python. We expect you to be a fluent reader and writer.

Tools we work with regularly (unordered):

• ML & NLP: PyTorch, Huggingface Transformers, Pydantic AI, Pandas, Spacy

• APIs & backend: Python, FastAPI, Pydantic

• Data & infrastructure: DuckDB, Snowflake, PostgreSQL, Docker, AWS (ECS, S3), Pulumi, Prefect, GitHub Actions

• Search & demos: Vespa, Streamlit

• Testing, evaluation & monitoring: Pytest, Hypothesis, Weights & Biases, PostHog

• Development tools: GitHub, Cursor, Claude Code

What will you be working on?

Climate Policy Radar’s core product is a search engine for 30,000+ climate documents. The engine is supported by classifiers that detect mentions of important climate concepts. In your role, you will:

• Work with programmes and platform teams to shape research and development priorities

• Develop, evaluate, and deploy state-of-the-art NLP models to extract structured information, focusing on small, efficient architectures

• Help build and deploy APIs to demonstrate new model capabilities for other teams to prototype around

• Contribute to building evaluation harnesses for search relevance, classifier accuracy, data quality, etc., to enable reliable cross-team iteration

• Implement approaches for data labelling or sampling to efficiently create training and evaluation datasets

• Analyse real user search logs and behavioural analytics to describe journeys and understand needs

• Research using LLMs to automate aspects of climate policy research and build evaluation datasets to maintain accuracy and bias standards

You bring with you

To hit the ground running in this role, we anticipate you will have the following:

• 3–5 years of experience tackling applied NLP problems with machine learning

• Demonstrated ability to move ideas from proof-of-concept to working implementations in partnership with other teams

• Excellent ability to write well-tested, maintainable Python code

• Strong working knowledge of applied machine learning techniques (supervised and unsupervised) and how to apply them to achieve good results

Nice to haves

In addition, we’d love to hear from you if you have experience with any of the following:

• Applying LLMs to highly structured or technical datasets

• Identifying and mitigating cultural biases in NLP models and datasets

• Building small, task-focused models with distillation, transfer learning, and fine-tuning

• Active learning, weak supervision, and zero/few-shot learning in NLP

• Deploying models to production in a user-facing context

• Building or analysing knowledge graphs

• Developing around Wikidata / Wikibase / Wikimedia

• Search relevance evaluation and optimization

We are looking for candidates who thrive in collaborative cross-functional teams and are excited by working in a startup/scaleup environment.

We are a mission-driven organisation and value alignment is important to us. We actively encourage applicants from diverse and historically underrepresented backgrounds.

Not sure if you tick all the boxes but align with our values and are excited about climate change and AI? Click apply — we’d love to hear from you.

Salary and Benefits

• Salary: £60k–£75k per annum, dependent on experience

• Wellbeing-focused policies including a 4 day workweek (same pay, Fridays off), unlimited annual leave, and a wellbeing allowance

• Vibrant, collaborative culture with emphasis on innovation and impact

• Hybrid work environment (2 days per week) in London, with current location at Sustainable Ventures in County Hall and a plan to move to TechSpace in Goswell Road. We welcome flexibility and remote work considerations

Interview process

Our interview process is designed to be transparent. After each stage, we will contact you within 2 working days to confirm whether you will progress.

• 30–60 minute screening call with our recruiter

• 60 minute remote behavioural interview with two team members

• Take-home task: 2–3 hours (scheduled to fit your availability)

• 60 minute interview to discuss your task

• 30 minute in-person final fit interview with CEO and Head of People

• Offer subject to references

Right to Work in the UK

We are not able to sponsor visas. Only applicants legally authorised to work in the UK will be considered.

Equal opportunities

Climate Policy Radar is committed to an inclusive, equitable workplace. We welcome applicants from all backgrounds and do not tolerate discrimination. We strive for equal opportunities for all, regardless of heritage, ancestry, national origin, citizenship, religion, sex, sexual orientation, gender identity, age, disability, relationship choices, or criminal history, in line with legal requirements. We also consider qualified applicants regardless of criminal histories, in line with legal requirements.

If you have a disability or special need that requires accommodation in the process of application and selection, please let us know.

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