My first advice to graduate students is always that they should follow their own motivation. That is, in my view, the key to success for the students and the main driver for scientific progress: only motivated researchers will make a difference, in academia and in society. But of course environment and development economics is a good choice: it is very relevant and intellectually challenging. Alleviating poverty and preserving a balance between the human sphere and the natural environment are the major issues of our world. The parts of the world that are still developing are also the parts of the world where important choices will be made on preserving this balance. This makes the field very relevant.

Environmental economics went through different stages. After a short period of attention in the early 1970s because of the alarming report of the Club of Rome, it really took off in the early 1990s. At that time the main debate was either to subscribe to what was called ecological economics or to environmental economics. Both approaches agreed that at that point economics had failed to take account of the balance with the natural environment. Ecological economics advocated developing a transdisciplinary approach to environmental problems, whereas environmental economics advocated an approach that builds on the body of economic knowledge. My advice to graduate students at that time was to choose the route of environmental economics but to look seriously at the natural sciences. For example, I had a student at the time who wanted to work on acid rain problems but who first took a course on soil acidification processes. Personally, I benefited a lot from contacts through the Beijer Institute with ecologists who taught me about regime shifts in ecological systems.

Initially, the field of environmental economics developed rather differently in different parts of the world. The main focus in the USA was on valuation, which may be classified as the most specific area of environmental economics, whereas the main focus in Europe was on theory and in the developing countries on applied research. After 20 years a lot of cross-fertilization has led to a broad established field that is practiced all over the world. The challenge is still enormous. Economic theory has to be rewritten in order to take account of the interactions with the natural environment, methods valuing non-marketed goods and services have to be improved, resource management especially on the global scale raises difficult issues, and data collection and applied research are still in their infancy. It is also important to become more visible in the societal debate. My advice to graduate students is to jump in there and to see it as a joy to be able to take part in this historic mission.

The field and its academic organizations such as the European Association of Environmental and Resource Economists and its North American counterpart have been very successful in the last 20 years but this may also have a drawback. One can build a career by participating in the yearly congress, publishing in the field journals and networking within this community. It creates a comfort zone for the researchers in this field. However, a lot of the research is still a simple twist of standard economics: integration with the insights of the natural sciences is far from completed. Moreover, new developments in economics only slowly trickle down into environmental economics. My advice to graduate students is to stay connected to economics in general and to open up to one of the areas in the natural sciences. Some choices are needed here, of course, because research has to go deep and cannot go deep everywhere at once.

Summarizing, my advice is this: go for it. The field is very important and challenging, but be aware of comfort zones and realize that innovation usually occurs when you cross the borders, to natural sciences and back to economics again.