Treating the symptoms of climate change
Authors: None The Lancet Microbe
Journal: The Lancet Microbe (2024)

Towards the end of 2023, a year now confirmed to be the warmest on record, COP28 (the UN climate change conference) concluded with the expected lukewarm commitments to tackling climate change at some point in the future. A significant failure was the implication that there is still space to delay the lion’s share of the required mitigations. However, other reports released to coincide with the COP28 spectacle highlighted that the impacts of climate change are being felt now, and so action must be taken immediately. One such report was from the Climate Amplified Diseases and Epidemics (CLIMADE) consortium. The CLIMADE report lays out the effects of climate change on epidemics that are evident now and the probable future outcomes if climate change is not addressed with the seriousness that it deserves. The first two calls for action are particularly relevant to our field: timely outbreak reporting and the strengthening of genomic surveillance. The report makes three further calls for action that reflect more general needs: prioritising vulnerable populations, promoting climate resilience, and committing sustainable funding. In their report, CLIMADE make the point that the interaction between climate change and infectious disease is being overlooked and that climate change has the potential to increase the impact of more than half of all known human pathogens. Bringing the urgency into sharp focus, their opening paragraph concludes with “this distressing phenomenon is not a distant projection but a stark reality currently unfolding before us”. The report also outlines the remote, but nonetheless real, possibility that melting permafrost could expose us to unfamiliar pathogens. So, the recommendations made in the report calling for effective and transparent vigilance are a straightforward recognition that climate change is our present not our future. Global leaders are acting (if they can be said to be acting) too late, because now we find ourselves in the position of needing to prevent exacerbation of climate change while at the same time needing to treat the symptoms of climate change. It seems the wisdom of the age-old adage that prevention is better than cure has been lost on those who could have made a difference. Fortunately, CLIMADE’s calls to action build on plans that are already in motion, particularly since the COVID-19 pandemic. A further report highlighting, in a UK context, climate change and its impact on health was published by the UK Health Security Agency (UKHSA). This is an update to a 2012 report. In the intervening decade the realities of climate change have come into greater focus. Within this comprehensive 15-chapter report, two chapters are particularly relevant to readers of The Lancet Microbe. Chapter seven examines the effect of climate change on infectious diseases and chapter eight outlines the direct and indirect effects of climate change on vectors and vector-borne diseases. Chapter eight of the UKHSA report is sobering reading for people who felt that the temperate climate of the UK meant it was somewhat removed from notable impacts on vectors and vector-borne diseases. The report states that the biggest risk related to vectors is the establishment of Aedes albopictus in the UK, a “mosquito species that can transmit several arboviruses of public health concern, including dengue, chikungunya, and Zika”. The area around London is already hospitable to this vector, and much of England will follow within the next 25 years. Most significant when contemplating action, is the likelihood that non-native vector species will be difficult to eliminate once established. The central recommendations made in the UKHSA report align with those made by CLIMADE: surveillance will need to be the centrepiece of response efforts. Only through effective surveillance will it be possible to prevent vectors and infectious agents from becoming entrenched. Warnings about the impacts of climate change have moved beyond undeniable now that the effects are being felt in more and more tangible ways. Although the COVID-19 pandemic made clear that greater disease surveillance is essential, the need to put relevant structures in place is more urgent than preparing for a hypothetical future pandemic from some hitherto unspecified agent. The policies, or lack of them, of high-income countries clearly demonstrate an outdated attitude of considering many infectious diseases as being limited to far-off lands, but climate change is redrawing the map for many infectious agents and their vectors.