Episode 1: The Evidence Behind Climate Change

[00:00:00] Sophia Gauthier: I’m going to read several headlines to you. All right. Number one, climate change. Polar bears could be lost by 2100. That’s from BBC News in 2020. Number two, climate change puts children’s health at risk now and in the future. That’s from Science News. And number three, NASA clocks July 2023 as the hottest month on record since 1880.

[00:00:28] Graham Aufricht: Wow. Okay. So the unifying theme is climate change. As two pediatricians hang out in a recording studio, I want to know, what do we need to know and how can we help?

[00:00:39] Sophia Gauthier: These are the most important questions that this podcast aims to answer. So I’m glad that’s what you asked. A few disclaimers to start off. So, you know, first, while we really aim to provide a broad spectrum foundational overview of this topic, it is by no means exhaustive.

There’s so much to be learned about. Climate and health. I’m still learning a ton. And second, climate change can be a pretty distressing topic, both from an existential and a personal experience perspective. So we just want to recognize that some of our listeners may be dealing with illness or personal loss from climate related events.

And we are thinking of you. We encourage you to never hesitate to seek assistance in those matters. Okay, let’s get started. So I am Sophia Gauthier. And I’m Graham Aufricht. We are pediatricians and hosts of this podcast, Clinicians, Kids, and the Changing Climate. For the purposes of this podcast, when we say climate change, we are referring to the concept that the Earth’s average temperature has been increasing since the late 19th century due to human activities and may continue to increase in the future, altering climate around the Earth as a

[00:01:49] Graham Aufricht: result.

In this episode, I’m looking for the basics. Tell me about the evidence behind climate change. How does this apply to our work as

[00:01:57] Sophia Gauthier: pediatricians? Okay, so I’m going to start by addressing your last question first. The World Health Organization estimates that 88 percent of the global disease burden attributable to climate change affects children under the age of five.

[00:02:12] Graham Aufricht: Wow. Okay, so that’s a significant majority. Uh, how is that calculated?

[00:02:17] Sophia Gauthier: I, I assume with great difficulty, but it’s based off of something called Disability Adjusted Life Years or DALYs for short. This is a time based measure. It combines years of life lost due to premature mortality and years of life lost due to time lived in states of less than full health.

So essentially morbidity. Additionally, children of lower socioeconomic Status globally bear the burden of climate related disease.

[00:02:45] Graham Aufricht: Okay. And what does the American Academy of Pediatrics say

[00:02:49] Sophia Gauthier: about this? So I’m super proud to say that in 2015, the AAP was the first major medical society to release a policy statement on the impacts of climate change on pediatric health.

[00:03:01] Graham Aufricht: So before we delve into those impacts, let’s talk about the evidence behind climate change. As a physician, what are the basics that I need

[00:03:08] Sophia Gauthier: to know? Okay, so in 2023, so this year, the Intergovernmental Panel on Climate Change, called the IPCC, this is an organization under the United Nations, released a synthesis report of their six assessments.

Essentially they’ve been releasing these different assessments on climate change over time. And in it, they explain that Earth’s average surface temperature has risen about one degree Celsius since the Industrial Revolution in the late 19th century.

[00:03:36] Graham Aufricht: This is in the context of the 2015 Paris Agreement on climate change, where countries from around the world agreed to hold average global temperature rise to, quote, well below 2 degrees Celsius compared to pre industrial levels, end quote, ideally to below 1.

5 degrees

[00:03:51] Sophia Gauthier: Celsius. The majority of this warming that has occurred in the last 40 years, this is demonstrated by the fact that each of the last four decades has been successively warmer than any preceding decade since 1850. Hmm.

[00:04:04] Graham Aufricht: Super interesting. All right, let’s talk about the evidence. How do we

[00:04:08] Sophia Gauthier: know this?

There is a fantastic graph in the AAP technical report that I mentioned earlier. Um, but you can sort of, you know, look at versions of this graph anywhere. It shows Earth’s average annual temperature since the 1880s. And in it, you’ll see major, like, year to year fluctuations. These are natural, they exist because of complex meteorological phenomena such as El Niños, La Niñas, as well as volcanic eruptions.

However, there is a clear upward trend since reliable record keeping in the 1880s. This upward trend is correlated with the average concentration of carbon dioxide in Earth’s atmosphere.

[00:04:44] Graham Aufricht: Carbon dioxide, like methane, absorbs long wave energy re radiated from the Earth and leads to a greenhouse effect of warming.

Carbon dioxide is naturally occurring, but is also produced by human activities, predominantly the burning of fossil fuels such as coal, oil, and gas.

[00:05:00] Sophia Gauthier: Evidence of global warming is further substantiated by satellite evidence of declining Arctic sea ice, decreased snow cover, glacial retreat, shrinking ice sheets.

So for example, summer Arctic ice extent is shrinking by about 12. 6 percent every 10 years due to warming temperatures. And if you’re more of a visual learner, there’s some really fascinating images on NASA’s website if you want to take a look.

[00:05:24] Graham Aufricht: So speaking of melting ice, tell me about sea

[00:05:27] Sophia Gauthier: level data. So melting ice contributes to about half of the measurable changes in sea level, and the other half is due to thermal expansion of warm water.

Since 1880, global sea levels have risen over eight inches, and this rise is accelerating. Projections with high greenhouse gas emission scenarios predict that sea level rise in the continental U. S. could be over seven feet by 2100. 2100,

[00:05:52] Graham Aufricht: okay. So far, we have focused on data from the late 1800s onwards.

However, that is a short amount of time in the Earth’s history. How does this period of time compare to the last several thousand

[00:06:03] Sophia Gauthier: years? Okay, I love that you asked that because this was exactly my question when I started learning about climate. So there have been several ice age cycles in the past million years or so.

These are natural fluctuations in Earth’s climate based on Earth’s orbit with respect to the sun. During the hottest peaks in Earth’s climate in this time period, atmospheric carbon dioxide levels never exceeded 300 parts per million. However, since the industrial revolution, they have since exceeded 400 parts per million.

It’s actually jumped about 50 percent from pre industrial levels. Annually, the rate of rise in atmospheric carbon dioxide over the past 60 years is 100 times faster than any previous natural increase, such as that seen at the end of the last ice age. Hmm.

[00:06:49] Graham Aufricht: How do climatologists know the climate and carbon dioxide levels before we started taking measurements in real

[00:06:55] Sophia Gauthier: time?

So just like the fossil record is like a freeze frame in time, we can look at sediments, coral reefs, tree rings, and ice cores. All of these things capture elemental signatures from the time period in which they were formed, giving us insight into the past. So, I say we, but Climatologists can use this data to reconstruct atmospheric and climate data from time gone, as well as use it to model what the future may look like under various scenarios.

My name

[00:07:23] Geeta Persad: is Geeta Prasad. I’m an assistant professor of climate science in the Jackson School of Geosciences at UT Austin in the Department of Earth and Planetary Sciences. Climate scientists model past and future climate by using essentially these giant global earth system models and these earth system models are more or less massive, uh, computer programs that take the Earth’s ocean and atmosphere and land and ice and split it up into three dimensional boxes.

And in each of those boxes, we calculate all of the equations of mass and energy that govern how conditions in that box are going to change through time. And then we also simulate how A box in one place on the planet is going to impact every other box on the planet. So as you can imagine, that is a lot of calculations.

And so these computer models are often run on these massive supercomputing centers. Physicians are very aware of how the environment that a person lives in affects their health. So, Um, whether they’re exposed to extreme and heat and humidity, um, how air quality where they live affects them. And that’s all really influenced by climate and atmospheric science, which is my area of expertise.

So my group’s work focuses on understanding how human activities and the air pollutants that are produced by human activities influence regional and global climate, um, using simulations. Um, and that includes a lot of the environmental exposures that I just mentioned.

[00:08:53] Sophia Gauthier: Okay, so that’s been a lot of information.

Let’s summarize the most key important takeaways from this episode. All

[00:08:59] Graham Aufricht: right. So in 2015, the AAP was the first U. S. medical society to release a report on the impacts of climate change on health with a focus on pediatric

[00:09:10] Sophia Gauthier: health. Second, the average global temperature of the earth has increased by about one degree Celsius since before the industrial revolution in the late 1800s.

[00:09:20] Graham Aufricht: Third, in the last million years of Earth’s history, carbon dioxide levels had previously never exceeded 300 parts per million. But now, in the last 200 years, we’ve exceeded 400 parts per million.

[00:09:32] Sophia Gauthier: There is so much information to unpack in the topic of climate change. impacts on the environment, but the rest of this podcast will delve into the impacts that climate has on pediatric health specifically.

So stay tuned for our next episode on heat waves, heat illness, and wildfires. This podcast was researched and written by myself, Dr. Sophia Gauthier. A massive thank you to my friend and co host, Dr. Graham Aufricht, as well as Dr. Geeta Persad for her insights into the world and work of climate scientists.

The podcast was produced by the fantastic audio engineers at the University of Texas at Austin liberal arts instructional technology services team with funding via a pediatric medical education grant and instructional support from the medical education fellowship at the University of Texas Dell Medical School.