We present daily estimates of country-level CO₂ emissions for different sectors based on near-real-time activity data. This is a new dataset developed during the COVID pandemic that substantially advances the frontier of emissions monitoring. It also represents the genesis of a new international research collaborative, Carbon Monitor.

Using 39 years of hourly U.S. weather data and a macro-scale energy model, we show that currently available long-duration storage technologies like power-to-gas-to-power lower the cost of solar-wind-battery electricity systems.

In the modern era of global observing networks, pervasive sensing and tracking of human mobility and behaviour, unprecedented COVID-19 disruptions are an opportunity for understanding the Earth System. We hypothesize Earth System responses along cascades of energy, emissions, climate and air quality, and poverty, globalization, food and biodiversity.

We show that stricter, shorter COVID lockdowns reduce overall losses relative to weaker but longer ones. But even a lengthy period of moderate restrictions is economically preferable to lifting all restrictions if it can avoid the need for another round of strict lockdowns. Regardless, losses propagate via global supply chains; best case responses are globally coordinated.

We show that ambitious climate mitigation scenarios entail drastic, and perhaps un-appreciated, changes in the operating and/or retirement schedules of power infrastructure. For example, in 1.5 or 2°C scenarios, the median age of global coal plants at retirement is <10 years.

By analyzing 35 years of temperature, ozone levels, and crop yield data, we estimate the impacts of warming and ozone pollution on perennial fruits and nuts in California. These crops, which represent ~38% of the state's agriculture by value, suffer damages of about $1 billion per year due to ozone in recent years. With 2°C of warming, almond yields will drop by ~10%.