The press release reflects well the content of the article. The study represents an interesting analysis of the OECD's ‘climate’ policy database and gives some very general indications of the apparent impact of these, including some combinations and some differences between developed and non-developed countries.

Its results should be treated with caution. The political and regulatory contexts of different countries may differ greatly in the impact of particular policies, so it is not generalisable which policies are best. Establishing the causality and intentionality of a measure is not easy given that some measures are highly interdependent and that sometimes the impacts are not due to the measures but to other causes (e.g. geopolitical phenomena that may affect fuel prices).

This paper has managed to assess the impact of hundreds of climate change policies in a clean and advanced way. Rather than measuring before and after policies, it has been able to detect changes in emissions and where these can be attributed to existing policies. I emphasise the value of open data, which allows researchers to conduct these important studies using state-of-the-art data analysis methods that provide us with the keys to making critical decisions for life on our planet.

This study demonstrates very important insights that, while not new, are reinforcing and calling for action in a certain direction. One of its main findings is that we need to address climate change with many different policies over time. Since the data for Spain link transport policies to the largest emission reductions on record, and mobility is my speciality, I will focus on this field. The concept of policy packages is not new in the field of mobility. More than ten years ago, Moshe Givoni and David Banister (key names in academic studies of sustainable mobility), at Oxford University, argued that policy packages could generate greater impact than the implementation of individual policies.

In the Spanish context, what lessons can we learn from the results of this study? First of all, we need to apply a comprehensive vision in mobility policies that is reflected in good planning instruments, our roadmaps. The holistic vision stems from the realisation that investing in only one type of policy does not help us to achieve the expected results (as this article manages to demonstrate) and provides a structure with which to work on varied and diverse public policy packages.

My work for years has focused on the holistic view of cycling mobility and I am involved in designing and implementing evaluation instruments for these policies. The results of this article reinforce the lessons I have learned throughout my career. Building infrastructure alone is not enough, we need to look at governance, education, information, social movements, regulation, planning.

The second tool is demonstrated by the article itself: carrying out quality impact assessment (ex ante). And for this, we need to invest in quantitative and qualitative measurements of what is happening to the environment, to people's health, to their social well-being. We are not doing enough of this and we are losing information to make the right decisions and justify how and why to invest in climate change. Investments in assessment must be part of any public policy implementation project.

In Spain, there are two ways in which we can do more quality evaluation: one is the publication of open data so that studies can be carried out; and the second is collaborations with universities and research centres that have the knowledge to carry out quality evaluations. Without quality assessments, we cannot obtain the scientific evidence on which to base policy decisions. This is the main role of science, let us use it to care for and heal life on our planet.