Having worked on the impact of climatic changes on endemic parasitic disease in the EU funded research project GLOWORM, I was asked to give a presentation on the impact of climate changes on animal diseases in general. I agreed with this question and made it part as one of the seminars offered by Kreavet. Reading myself into the subject, it became rapidly clear that there are two sides to the coin: a) several livestock diseases even not vector borne diseases are sensitive to climate change and b) controlling animal disease is a critical part to reduce greenhouse gases (GHG) from the livestock sector.
Livestock considerations have become an intrinsic part of proposed actions to tackle climate change. The usual suspect is cattle in general and beef cattle in particular, because of all livestock species, they are the largest emitters of potent GHG. Reports and opinions to promote reductions in meat consumption to mitigate human impact on climate change are daily in the news.In Belgium, it was recently argued that the country’s livestock population should be halved by 2050 to reach the agreed Paris climate targets .
Let’s first try to put things in perspective and look how GHG emissions from livestock compare to other sectors, at least at the EU level. GHG emissions went down by 22% between 1990 and 2016 . These reductions come from the energy sector, industry and agriculture. Only transport, after a drop following the economic crisis of 2008 has increased since 1990. On the EU-level, GHG emissions from agriculture (including livestock) remain stable around 11%, while transport has increased and now represents 25% of the total emissions . So, when on a Belgian TV show, a celebrity teaches 16-year old students that the meat sector alone pollutes more than the whole transport sector and reduced meat consumption would be a solution, this does not seem accurate. Moreover, if we reduce meat consumption, what will we do with the unspent budget? I can imagine other things like travel, buying electronic devices and exotic foods, all of which can have a greater impact than the piece of meat we would no longer eat.
This does not mean that the livestock sector can sit back and deliver no further contribution. First, it seems that quantifying emissions could still benefit from better estimation methods. Animal methane emissions show great variation depending on production system, diet, age and animal productivity. However, current estimation approaches are based on standard emission factors, multiplied by the number of animals in the population. If there is no good methodology, also impacts of mitigation strategies cannot be monitored. Second, according to the Food and Agriculture Organization of the United Nations, 30% of the emissions from livestock can be cut by adopting current best practice and technologies in feeding, health, husbandry and manure management . Although, the greatest potential for cuts is in low productivity systems in developing countries, small reductions in developed countries can lead to significant gains in absolute emissions given the overall large volume of production. Third, promising innovations are in the pipeline with the potential to further cut emission volumes. Breeding solutions and novel feed additives promise to reduce GHG emissions of ruminants by half. Better disease control enhanced through improved vaccines and diagnostics have the potential to improve production efficiency by 20%; and the digital revolution in livestock farming, promising further gains in efficiency is about reaching cruising speed. Remarkably, lab-grown “meat” is considered to have a similar ecologic impact as proteins from animal origin.
In a recent policy report  however, it is argued that implementing best practice and innovation will not suffice and that the European livestock numbers will need to be significantly reduced in order to be in balance with environmental objectives. In the end, also innovation has its limits and as in any growth model, progression margins become smaller as we proceed. However, should we ask ourselves how many livestock the planet can carry, or rather how many people? Current scientific insights more and more point out that we have surpassed the sustainable human population threshold and there is need for global policies that reverse population growth . All the other things, too many e-packages, too many air planes, too many animals are just consequences of that.
 ‘Vlieg minder. Eet minder vlees. Pak e-commerce slimmer aan’, Knack nr 33, 15/08/2018.
 Eurostat, 2018. Trends in greenhouse gas emissions. https://ec.europa.eu/eurostat/statistics-explained/index.php/Greenhouse_gas_emission_statistics#Trends_in_greenhouse_gas_emissions.
 European Environment Agency, 2016. Sectoral greenhouse gas emissions by IPCC sector. https://www.eea.europa.eu/data-and-maps/daviz/change-of-co2-eq-emissions-2#tab-dashboard-01
 Gerber, P.J., Steinfeld, H., Henderson, B., Mottet, A., Opio, C., Dijkman, J., Falcucci, A. and Tempio, G., 2013. Tackling climate change through livestock – A global assessment of emissions and mitigation opportunities.Food and Agriculture Organization of the United Nations (FAO), Rome
 Buckwell, A. and Nadeu, E. 2018. What is the Safe Operating Space for EU Livestock? RISE Foundation, Brussels
 Crist, E., Mora, C., Engelman, R., 2017. The interaction of human population, food production, and biodiversity protection. Science 356, 260-264.