Renewable energy technology has advanced substantially in recent years, and countries are heavily investing in green energy to mitigate the negative effects of climate change. In 2020 21 percent of all energy in the United States was sourced from renewable technologies, with wind and solar energy increasing 14 percent and 9 percent year-over-year, respectively.

Still, the burning of coal, oil, and natural gas, among other fossil fuels, accounts for roughly 75 percent of global greenhouse gas emissions. This must be much lower to slow global warming, meaning governments need to continue to increase renewable energy investments. The following are four examples of how burning fossil fuels has impacted weather systems and seasonal patterns.

Hottest Global Temperatures in 125,000 Years

Our dependence on fossil fuels could have drastic impacts on the future of the planet, suggests a new report from the United Nations Intergovernmental Panel on Climate Change (IPCC). The report, released on August 9, was compiled by more than 200 scientists and approved by 195 governments. The key finding of the report is that the Earth's global surface temperature is the hottest it has been in more than 125,000 years.

Moreover, the IPCC estimates that without a substantial reduction in fossil fuel dependency, average global temperatures could rise by as much as 3.5°C (38.3°F) above pre-industrial levels by 2050. Maisa Rojas, one of the lead authors of the report, suggested that the 1.5°C (34.7°F) threshold laid out in the 2015 Paris Climate Agreement can only be achieved with "immediate, rapid, and large-scale reductions of all greenhouse gases."

Unpredictable Seasons

Rising global temperatures aren't the only concern regarding climate change. Seasonal weather patterns are also changing and, in the United States, spring arrives an average of six to 19 days earlier than it did seven decades ago. This might sound appealing, but it has several negative consequences. Plants that bloom before pollinators emerge from hibernation can die off early, and migratory birds can have trouble securing previously reliable food sources. Seasons will become even more unpredictable without a massive decline in greenhouse gas emissions.

Lyme Disease

At least 5 million premature deaths per year are attributed to local air pollution caused primarily by fossil fuels. However, this isn't the only negative health impact of global warming. Infected black-legged ticks have spread throughout the United States due in large part to warmer temperatures and shorter winters. As a result, Lyme disease infections in the country nearly doubled from 1991 to 2018.

Flash Flooding

Flash flooding is one of many catastrophic climate events associated with global warming. At least 220 people died in July 2021 after extreme rainfall transformed swollen streams into raging rivers in Germany and Belgium.

The World Weather Attribution subsequently released a study examining rainfall from the end of the 19th century to 2021 in the Western European region spanning the Netherlands to Switzerland. Global temperatures increased by 1.2°C (34.16°F) in this time, while the average rainfall for a single day increased by 3 percent. Moreover, study authors estimated that downpours like the one in Germany and Belgium are now 1.2 to nine times more likely than they were in the 19th century. This is because the air can absorb more water as the planet gets hotter.