A Year at the Breach

Just a few days ago, several news sources reported that the world breached the 1.5 degree celsius threshold of warming in 2024.

Given all the emphasis that has been placed on this 1.5 degree threshold, I wanted to take a closer look - at why warming matters, where the 1.5 number came from, and what our exceeding it in 2024 really means. Below is a summary of what I concluded.

Why does warming matter?

Earth system scientists have quantified nine boundaries that are considered particularly important to planetary health - one of which is climate. Changes in global average temperature reflect changes in the amount of energy within earth systems. Over time, these imbalances disrupt the weather patterns created by these earth systems. They can also move earth systems toward tipping points - thresholds which, if crossed, can create feedback loops that aren't reversible by any methods humankind has access to today.

How does human activity affect warming?

Over time, human activity has been creating a higher concentration of greenhouse gases in the atmosphere. The concentration of greenhouse gases is very closely linked to the global temperature - so much so that scientists can now predict warming with a high degree of precision based on predicted increases in greenhouse gases.

Although the amount humans contribute is relatively small in comparison to the overall natural cycles, more is being created than can be naturally re-absorbed, and a surplus has been accumulating for many decades.

Where does the 1.5 degree threshold come from?

A global scientific consensus estimated that 1.5 degrees of warming to be the upper limit of relative safety, above which some of the tipping points become more likely. By setting this as a threshold, scientists were able to calculate the amount of CO2 that could still be emitted before the 1.5 degree threshold was reached. This amount, referred to by policymakers as the carbon budget, formed the basis of the 2015 Paris Agreement, the United Nations' global treaty developed to address these risks.

Does the 2024 average mean we have exceeded the 1.5 degree limit?

Not yet. The Paris Agreement target is calculated using a 20-year average, to account for other factors that can cause global temperature fluctuations (e.g. El Ni?o and La Ni?a). However, the fact that warming has already exceeded 1.5 degrees suggests the threshold may be reached earlier than the scientific consensus originally estimated.

Practically speaking, what does this mean?

While reducing greenhouse gases will continue to be extremely important, we are likely to see increasing emphasis placed on resilience. For healthcare leaders, this will mean bringing environmental considerations into the preventative work already going on in communities. Here in the U.S., the Office of Climate Change and Health Equity recently released an updated U.S. Climate Resilience Toolkit, along with an online dashboard of climate change and health equity indicators. The American Hospital Association has also begun a multi-year initiative to help equip hospitals with the resources they need to prepare.

Outside the workplace, it is important to understand risks that may increase over time in the community you live in. The ready.gov provides many resources to help assess vulnerabilities and plan for potential disruptions of all kinds. One of the most important sources of resilience comes from building supportive relationships. Doing so will strengthen any future adaptive responses needed.

Upcoming events/deadlines

• [call for abstracts] - World Hospital Congress. (Accepted until Feb 28, 2025). The World Hospital Congress 2025 will take place Nov. 10-12 at the International Conference Centre in Geneva, Switzerland. The Congress brings together forward-thinking healthcare executives from across the world, and features an entire track on Environmentally sustainable, resilient, and low-carbon healthcare - among the many other urgent challenges we all share in common. Abstracts can be submitted here.
• [call for research] - Seeking submissions on Planetary Health Leadership. (Accepted Jan 1 - March 30, 2025). BMJ Leader is issuing this call to begin building an evidence base for what it really means to lead with people and planet in mind. More information is available here; you can also read the editorial Rammina Yassaie and I wrote for context here.
• [convention - clinicians] - Our Planet, Our Health: 2025 Climate Action Convention (March 1-4, Washington DC + Online. CME eligible.). One of the largest events ever focused on planetary health and climate action, with sessions being held at the National Academy of Sciences and the Hopkins Bloomberg Center. Attendees will gain insights into cutting-edge research on the links between ecological drivers and health outcomes, explore strategies for building resilience and equity in the face of climate challenges, and learn how to build capacity for science-informed policymaking. More information and registration available here.
• [workshop - healthcare leaders] - Unlocking Leadership Skills for Resilient and Lower-Carbon Healthcare (March 23, Houston, TX, ACHE Congress). Successful sustainability programs can yield numerous dividends - including financial savings, talent attraction and enhanced employee engagement, as well as supporting health equity goals. To learn more, join us for this full-day program which will include sessions with Dr. Jonathan Perlin, CEO of the Joint Commission, and Carrie Owen Plietz , President of Kaiser Permanente's Northern California Region. More information and registration are available here.

What are your thoughts on the 1.5 degree breach, and how we continue to adapt? As always, I welcome your comments. Thank you for reading, and your help healing our future.

Andy Garman