Miskatonic University Press

ℝ> library(tidyverse)
ℝ> library(lubridate)
ℝ> library(ggplot2)
ℝ> read_csv("https://raw.githubusercontent.com/wdenton/noa2co2/master/mauna-loa.csv", col_names = c("date", "co2")) %>%
   mutate(month = floor_date(date, unit = "month")) %>%
   group_by(month) %>%
   slice(which.min(co2)) %>%
   ggplot(aes(x = month, y = co2)) +
   geom_step() +
   labs(title = "Minimum monthly CO₂ at Mauna Loa",
     x = "Month",
	 y = "CO₂ PPM",
	 subtitle = "Data from https://github.com/wdenton/noa2co2",
	 caption = "CC-BY William Denton") +
   theme_minimal() +
   theme(axis.title.y = element_text(angle = 0),
         axis.title.x = element_text(hjust = 0))