I’m a PhD student at the MRC-PHE Centre for Environment and Health, Imperial College London (ICL), UK. I’m the first author of a recent study in eLife, which showed that young men in the US are more likely to die in summer, while older people are more at risk in winter regardless of the regional climate, which may have implications for climate change and future health. Ask me anything!

I’m interested in examining how climate change and extreme weather may be influencing the patterns and trends in mortality rates from year to year. My research includes building mathematical models both to analyse past trends of seasonality of human mortality and to forecast possible futures for climate change risk assessment. I work jointly with Professor Majid Ezzati at the School of Public Health and Professor Ralf Toumi in the Space and Atmospheric Physics group, both at ICL.

Our recent work involved analysing US death rates over a 37-year period. Our study, published in eLife last month, identified several distinct seasonal patterns relating to age, sex and disease, including higher summer deaths in young men. We also showed that this seasonality is similar across diverse climates with substantially different temperatures. We hope this work will help inform public health strategies to reduce deaths now and in the future. I’ll be here to discuss these findings and answer questions about our research more broadly. You can read the full eLife paper here, and use the annotation tool to make notes and discuss the work further. A plain-language summary is also available here. AMA!

My proof: https://twitter.com/imperialcollege/status/1060475810858045440

You can also connect with me on Twitter: @rmiparks

Comments: 712 • Responses: 53  • Date: 

fiahhawt469 karma

Wouldn’t an uptick in deaths among young males during the summer be the usual trend of men being more likely to do stupid shut that gets themselves killed? They just get out more and spend more time with other guys when the weather is nicer.

But on the topic of why the deaths occurred, unless they are caused by environmental exposure - heatstroke, hypothermia - how do you intend to argue that the environment killed them?

-1KingKRool-213 karma

Exactly my thoughts. Summer tends to see more people doing more activities outside, and young men tend towards doing riskier things.

eLife_AMA151 karma

Yes that sounds plausible.

I don't argue that the environment necessarily killed younger people. Warmer weather, however, can module behaviour too, which can cause more dangerous behaviour for younger people.

Slamsonitex148 karma

If someone were to argue against you about the detriment of climate change, what are 2-3 studies you would recommend them to read to convince them?

eLife_AMA215 karma

The Skeptical Science website has an excellent guide of how to respond to climate skeptics:


modswillburninhell72 karma

where is the safest place to live?

eLife_AMA181 karma

I think the definition of 'safest' will vary from person to person. I wouldn't want to make the ecological fallacy of suggesting that one person's life will be a reflection of the statistical models which calculate risk of death and life expectancy.

The country with highest life expectancy in the world will change over time, and may in the future be South Korea. But that doesn't mean just moving to South Korea will help you.

The best advice I can give for things which you can control are to eat well, exercise regularly, sleep enough and fill your life with things you are challenged by but interested in.

HasStupidQuestions21 karma

What datasets did you use and what, if any, adjustments did you make? What are the shortcomings of datasets used in your studies?

eLife_AMA14 karma

You can find the data locations online via the paper in the 'Figures and data' section at the bottom:


cersei_and_jaime21 karma

How is your data broken down by type of death? Also, are you counting deaths related to catastrophic weather events (such as the fires in California, or hurricanes)? Or are you only analyzing correlation at this point?

eLife_AMA15 karma

Data is broken down into cause of death by the ICD-9 and ICD-10 coding from the individual death records.

8Reai17 karma

We hear a lot about the rising temperatures of our Earth, but what about the cold winters? I live north of the snowiest city in the US and we have consistently been getting over 180 inches of snow per year for the past five years. Only a couple of times did this occur in the 2000s. We are getting longer and hotter summers and longer and colder winters. Is the cold winters due to climate change and the warming of the Earth? And if so, what steps do we need to take in order to fight this change?

eLife_AMA26 karma

There is evidence that climate change is creating more unsettled, at times colder, winter, yes.

Climate change is a difficult issue. We need changes in our lifestyle, but we also need strong government action. Joining civil society groups and petitioning government is an excellent way to help convince them. Contact your local representatives and seeing what s/he thinks for example will be a good start.

WhatTheFuckKanye13 karma

So, how long do we have on Earth?

eLife_AMA33 karma

Well there's no Planet B so hopefully a long time.

iswamwithwhales8 karma

I recently started medical school after working as a designer, dealing with chiefly with climate change topics (some practical and applied, some purely artistic and museum based). So I first want to thank you for doing this research, this is genuinely inspiring. You're showing me just how possible it is to do research in this area!

What I see a lot in my public health classes is an important and massive focus on nutrition. Nutrition particularly, is very much connected to climate change issues, yet I've never heard a single word about climate and environmental problems in my curriculum. For example, we continously get often get presented ideal and balanced nutritional profiles that don't take into account the environmental consequences of that food.

Where do you think does this inability by the medical world at large to take climate change into account lie, and how could we approach integrating it more?

What other diseases and threats to human health can we expect with more warming?

eLife_AMA12 karma

Thank you for your interest in and inspiration from my research.

There is a growing appreciation of the need to module nutrition to aid the fight against climate change. A good study recently came out in the Lancet Planetary Health journal30206-7/fulltext). There are others also.

You can find a good start on threats to human health in this paper.

theendisneah7 karma

Any correlation being made to mortality through increased violence catalyzed by hot temperatures?

eLife_AMA6 karma

Wrestle4Ever7 karma

Climate has been changing constantly, sometimes even drastically, for millions of years, and yet we've survived. Just a few days ago I stumbled upon this article about 536 being the worst year in recorded history, and read that about 10,000 years ago a large portion of mankind has been killed due to lighting storms and radiation (JRE podcast with professor Robert Schoch). How can we be so sure it's bad and because of us, if much worse had happened, long before modern technology?

eLife_AMA9 karma

Because climate change is causing changes at a far faster rate than society can cope with.

theorymeltfool6 karma


Less people are dying every year.

People are living longer than ever before

Given the data, it seems like an increase in “global warming” correlates to an increase in lifespan and a decrease in the global mortality rate. Obviously, correlation =! causation. Not sure how you’ll be able to account for all these factors and still produce a scientifically rigourous document.

eLife_AMA10 karma

You can build regression models which account for long-term trends in, as well as other factors.

Please keep an eye out for more of my forthcoming research, which I hope will answer your great question.

dlmcleo15 karma

What is your opinion on the study recently issued by the IPCC, essentially giving us a 2030 deadline for corrective action?

eLife_AMA11 karma

I think we need radical action. There is no doubt. Major changes in legislation and societal behaviour are going to be necessary. It is possible, but we need global unity in this time of crisis.

prginocx5 karma

Mr. Parks,

How much blowback does a Scientist in the UK get if they say anything in opposition to Global Warming theory ?

eLife_AMA0 karma

Thankfully quite a lot! Fortunately not many scientists disbelieve in climate change:


I have never met a single scientist who has looked at good-quality evidence dispassionately and disbelieves in climate change.

Historian10664 karma

What is the most effective way to fight climate change? For example, if I won $1billion in the lottery and wanted to use it to reduce the problem of climate change as much as possible, would it be better to invest in renewable energy or preserving a rainforest?

eLife_AMA11 karma

I would suggest that civil society puts pressure on governments to act on climate change as soon as possible.

Both of your suggestions are essential. I would only say that I would tend to avoid geoengineering solutions.

StefVC4 karma

Is there a question you hoped/expected to be asked that has yet to happen? If so, please ask and reply it!

eLife_AMA4 karma

I am greatly enjoying all the questions being asked.

I invite more to be asked, though!

Chtorrr4 karma

What is the scariest thing you have found in your research?

eLife_AMA10 karma

I try to stay dispassionate when I carry out my research, as I think it helps to perform scientific analysis.

However, I cannot pretend that I have not found anything that concerns me about the future of health under climate change. In particular, I have concerns about the increase in injury deaths, including suicides and transport deaths, under the onset of climate change.

A great paper by Marshall Burke et al. here is a good start.

artudituu13 karma

Which places will be most affected from climate change?

Also can we like stop climate change or is it too late now?

eLife_AMA4 karma

No place will be unaffected by climate change. Unfortunately those who have contributed the least to climate change will be affected the most:



It's not too late to stop climate change. As the recent 1.5 IPCC report states, we have limited but definite time to turn things around.

the_edgy_avocado3 karma

How would you overcome private company lobbying, influencing and weakening climate change policies in America? This pretty much only applies to America due to how much influence business has on politics over there, especially oil unfortunately.

eLife_AMA5 karma

Getting money out of politics.

kyotofly3 karma

Do you believe a change in location could cause change to a person physically? For example let’s say a person from Nigeria moves to Switzerland at the age of 2 and spends the rest of their life there, would they develop physical changes opposed to Nigerians who have lived in their home country their whole life?

eLife_AMA8 karma

Yes absolutely. While genetics (or nature) will explain a good deal of variation around the world, your environment (or nurture) also has a massive part to play in your health outcomes. Classic nature vs. nurture debate.

There are also interactions between your genes and the environment, in a field of study called epigenetics.

So yes.

Grimreq3 karma

I often see healthier looking people in colder climates. But also know there are high substance abuse and suicide rates. Does your research shed any light on this?

eLife_AMA4 karma

Societies adapt to their local climate. There is evidence that those living in colder climates are affected less by seasonal variation than those living in more temperature climates in Europe:


Intentional deaths have also been linked to increasing temperatures over time:


A lot about substance abuse and suicide rates, however, will depend on the specific country and community you are examining. Comparing northern Sweden to Siberia, for example, will have many different confounding factors such as income, availability of substances etc.

stantonisland3 karma

How do you stay positive spending so much time on a depressing topic especially when so many people in power completely discredit all of your work?

eLife_AMA30 karma

Some people in power may discredit my research. However, there is a large and growing majority of civil society and in fact those in power in most countries who accept the scientific method.

Climate change is no longer Climate change and the risks it poses to health is well-documented in thousands of papers.

I believe that opinion will change to lay on the side of science.

BrownJeezus6032 karma

What do you think is the easiest way to convince a climate change skeptic that they are wrong?

eLife_AMA1 karma

Good evidence should always defeat lack of evidence or bad evidence.

Skeptical Science is a good start:


Jon_Boopin2 karma

How helpful is a plant-based diet in reducing how much of an impact an individual puts onto the climate?

JordanNexhip2 karma

Is climate change real?

paparupara2 karma

How do you go about facing climate change deniers being that your investigation centers around the assumption that is happening and will continue to happen?

eLife_AMA3 karma

I try to put my efforts into making the best and most convincing research that I can.

Civil society will have other ways to convince climate deniers. That is an essential part of the fight against climate change.

Riki19962 karma

What do you think about people switching from fuel cars to electric cars?would that cause more or less pollution according to you?

eLife_AMA12 karma

In the mid-term (next couple of decades) societies around the world will need to decarbonise and increase renewable energy usage. Electric cars are only as clean as the energy which supplies them. While electric cars will reduce pollution in cities, increasing health, if the source of the electricity is from fossil fuels, they will stay make a significant contribution to anthropogenic climate change.

There is also evidence that production of electric cars (especially batteries) contributes to greenhouse gases, but much less than over a comparable diesel car's lifetime. (https://www.sciencedirect.com/science/article/pii/S1361920916307933)

BUT there is no doubt that electric cars are part of the future of transport. Also part of the future will need to be changes in behaviour and increased usage of mass transit. That requires a lot of infrastructure planning and investment. Further, we will need investment in renewable energy that will power electric cars.

shelly123456782 karma

Have you read American War? If so, do you think this type of fossil-fuel-driven conflict is likely?

eLife_AMA6 karma

I have not but thanks for the link. I think very likely is a great risk of climate refugees, who are fleeing uninhabitable places due to heat, natural disasters, and lack of water.

This is a great sleeping giant which we need to think about.

Suede_Cacti2 karma

Bit different - how are you finding life as a PHD student in London? Does your stipend cover your living costs? What are your hopes in terms of career progression?

eLife_AMA3 karma

Thank you for this question.

It is a great pleasure studying as a PhD student in London. My stipend covers my living costs, but not by much. I prepare a lot of my own food, I only go out every so often.

Finding good friends with shared interests is difficult, but a great way to keep costs down. There are so many social and free things to do in London, it is unreal.

The weather is sometimes a bit rubbish (like right now), but no more so than a lot of other places.

I hope to continue researching via a post-doc once I've finished my PhD.

Oh_god_not_you2 karma

Are you focusing more on third world ( terrible terminology I know but it gets a complicated point across in as few as words as possible) countries or are you including mortality in the industrialized 1st world nations as well? If you are I’m curious how you are eliminating other factors that are specific to the change in the industrialized 1st world?

eLife_AMA2 karma

You can control for confounding factors such as income etc. in the type of analysis that I do.

RuDy_XDD271 karma

Hey Robbie. I have 2 questions for you

Do you think humans will wait untill every bit of non renewable energy is gone?

Are energy sources like solar and wind really leaving a smaller carbon footprint?

Thanks in advance

eLife_AMA7 karma

Do you think humans will wait until every bit of non renewable energy is gone?

I hope not as that would be a disaster.

Are energy sources like solar and wind really leaving a smaller carbon footprint?

Most certainly

RestingBitFace1 karma

What's the most frustrating thing you've heard someone claim about what you're studying?

eLife_AMA9 karma

That climate change will be good because we'll be able to grow better wine in Kent, England.

memedealer221 karma

I know the trend in recent years so for places to get warmer but are there any outliers where it's getting colder?

eLife_AMA6 karma

Not on a climate-scale length of time (30-year averages).

Something to be well-aware of, though, is that one cold winter does not mean climate change and global warming isn't real. In fact, because of warming temperatures, the polar vortex may be disrupting locations and causing colder, more unsettled weather.

karmagetcha1 karma

Have you looked at your results by developing vs. developed countries? If so, was there a significant difference? I imagine you might have to control for the difference in life expectancy (but not sure how)?

eLife_AMA7 karma

No but it is something I'd be interested in looking into. The difficulty with some Low and Middle Income Countries is the availability of high-quality health data.

What I do know if those most vulnerable to climate change live in the poorest countries:


kittylover30001 karma

What measures can we take to protect the inhabitants of nations at risk of total submersion? (i.e. persons living on the Solomon Islands, the Republic of Kiribati, the Republic of Fiji, etc.)

eLife_AMA1 karma

Mitigation of greenhouse gases will be the first and immediate action that needs to take place.

Places such as the ones you mention do not need total submersion to be a risk. Flooding for part of the year will make the islands essentially uninhabitable.

AvgBro1 karma

What academic/peer reviewed articles are a must-read in your community? I constantly find myself in situations where family question the validity of “climate change”, and would like to have some solid science ready to present this year during the inevitable discussion about how the weather on Christmas is different because “X”.

eLife_AMA2 karma

I would start with Skeptical Science


Jamides1 karma

How does your work be considered into policy? What does a policy that reduces death, based on your recent work, look like?

eLife_AMA2 karma

More attention being paid to older people during winter. There is a lot of attention already, but the past 40 years or so have not seen any large decrease in the relative difference between summer and winter mortality for the oldest age groups. People are living longer and older people need to maintain their quality of life.

If you have older relatives, stay in communication and visit them more often. From a government point of view, more investment is always needed for social care.

You can see that evidence in my paper here:


PorridgeWashington1 karma

Has your research been affected by the Trump administration purge of climate data from federal agencies?

eLife_AMA1 karma

It hasn't affected it at all, luckily. However, the lack of transparency and disinformation campaign about climate change is a worrying phenomenon.

harrypottersdragon1 karma

If I have grandkids down the line (I’m in my 20s) what would their generations’ health problems look like because of the climate? I’m assuming the earth would be at overpopulation by then.

eLife_AMA1 karma

It depends where they live. Disease prevalence and deadly heat prevalence will change.

Skow13791 karma

Do you consider all extreme weather related to climate change?

eLife_AMA2 karma

Any one extreme weather event would be difficult to attribute to climate change.

However, there is an increasing trend in extreme weather events, such as heat waves and cyclones, which have been analysed and attributed to climate change.

eLife_AMA1 karma

Thanks for taking part in this lively AMA. Please follow Robbie Parks on Twitter as he would always love to continue the conversation: @rmiparks

YoungZM1 karma

How do you seek to resolve those disinterested in climate science and to keep an open mind to your report? Is there a way to visualize the data from your findings by putting a human face to it and make it harder to ignore?

It must be frustrating that while actively engaging in a study that might strengthen the case of climate change when people await its release simply to immediately call it fake/discredit its validity.

EDIT: I find it somewhat disappointing that my comment is being downvoted with similar vigor to other commenters questioning if warming exists and another simply insulting the OP. Creating effective studies that communicate the importance of the issue based on its conclusion to the population is crucial in making them usable to the average reader. Loading scientific journals with studies is an important task in and of itself but if we're ineffective in convincing any individual that this matters, it will all be for naught. We have numerous reports on climate sciences and why it matters to act now - what we don't have is reports that communicate to people who are close minded on these issues to consider their position now. We can see day-to-day that people don't care about something as abstract as their child's future - if they even intend on bearing children. We need people concerned about the present (themselves).

Thank you OP for your answer all the same!

eLife_AMA2 karma

A good way of thinking about CO2 and greenhouse gas emissions is to think of them as 'carbon pollution'. People 'get' pollution. Pollution levels, while unacceptably high in many parts of the world, have reduced dramatically in the US over the past few decades thanks to regulation and the EPA. If we think of the futures we will leave our children, I think it should stimulate us into action.

My responsibility as a scientist is to be as engaging as possible to all who would like to know about my research. That is how I hope to resolve those disinterested in climate science and its impacts. I believe that if the scientific community can continue to communicate well, we will help. Once others outside of science are on board, the message spreads quickly.

Captroop0 karma

I think part of the problem is so many older folks won't be around long enough to be proven wrong when it comes to the worst effects of climate change, and can live out their years content that climate change is a myth. What is a more immediate consequence of climate change we can show them that is empirically provable so we can get more on board and start making changes now?

eLife_AMA5 karma

I think if you look at the cyclones in the USA, they are potentially already an immediate consequence of warming ocean temperatures:


The increase in global temperatures, with record temperatures over the last few years, also show that increasing temperatures is a trend rather than a blip:



The evidence is there and plain to see.

ViralRiver0 karma

How do you have time to do this? When I was at Imperial I didn't have time to eat let alone do an AMA...

eLife_AMA2 karma

I think I'm going to have a late night working tonight!

Calembreloque0 karma

This looks like an exhaustive study, these trends are very interesting! My question: from the results of your study, what sort of societal changes do you expect to be likely, based on these differences in mortality? Do you think the tendency of summer temperatures to kill younger people (temperatures which are to become more frequent as climate change intensifies) will result in a larger demographic imbalance in the US?

eLife_AMA1 karma

Thank you for finding my research interesting. I am glad I am not the only one :-).

Demographic imbalance may shift depending on birth rates. One may see, for example, in the near-future, governments recommending having fewer children and adopting more. A long-term large-scale trend is an aging population in any case. The implications this may have for the economy is something I am no expert on, sadly.

filthylittle2340 karma

Will the US ever actually stop the damage its doing? or will PHDs like you just get educated to observe the world burn?

eLife_AMA2 karma

There is a great movement from civil society in the US, as well as other places, which are committing to carbon-free economies. The entire state of California has now committed to be zero carbon by 2045. Some of the biggest cities around country are also committing to tackling climate change head-on.

I will avoid being political, except to say that I believe in the scientific method, which overwhelmingly agrees that climate change is real and human-made, and that it needs to be acted on. I remain optimistic.

wbtjr-2 karma

why do you say your name like anyone knows who you are?

eLife_AMA3 karma

I barely know who I am sometimes. Effects of PhD I think.