The causes

As one might expect, the more solar radiation that reaches our atmosphere, enters it, and gets trapped within it, the hotter our average temperature becomes. All three of these factors work together to maintain the delicately balanced climate necessary to sustain much of Earth’s life.

So what’s to blame for our current warming?

Over time, insolation is pretty predictable. The sun’s output follows an 11-year solar cycle, and the amount that reaches our surface depends only on our orbit and axial tilt – also very predictable things by now, if clothing store prices are anything to go by. The effects of increased insolation are obviously quite hard for us to prevent, but thankfully they are short-lived and not responsible for our current warming trend.

The amount of particulates in the Earth’s atmosphere, from things like volcanic eruptions, is much less predictable, and can have more noticeable consequences. The diagram to the right, taken from NOAA data, shows the reduction in solar radiation passing through the atmosphere at the Mauna Loa Observatory after some recent volcanic eruptions in the area. At an extreme level, the volcanic eruption of Huaynaputina in 1600 caused the coldest year in six centuries, leading to the Russian famine of 1601-03 which killed two million people. Lucky for us again, beyond these short timescales, eruptions don’t factor into our calculations.

This leaves us with greenhouse gas levels, which have also risen and fallen historically in less predictable ways. Carbon dioxide, being the product of animal respiration, is the most common of these, and a graph from NASA of its prevalence in the atmosphere over time is on the left. Despite the graph’s erratic, spiky nature, one big spike in particular might stand out to you.

In short, while all three of these factors – insolation, particulates, and greenhouse gases – can contribute to changes in Earth’s temperature over time, the most significant and pressing factor in our current period of warming is the accumulation of man-made carbon dioxide and methane in the atmosphere. We must change our habits dramatically if we are to reverse this warming trend.

The effects

Increasing average temperature does more than just melt polar ice. With each fraction of a degree of warming, more energy from heat is built up in the atmosphere, which is then dispersed by bigger and more destructive weather events. Heat also changes how weather is distributed around the Earth by affecting the speed of the jet stream, putting infrastructure and people around the world through unfamiliar weather conditions and endangering ways of life across the planet.

Just some of the effects of climate change are:

Severe Weather Events

Severe weather events such as hurricanes and flooding are amongst the most devastating effects of climate change. Loss of life and property, contaminated water, and the spread of waterborne illnesses are common fallouts of water-related disasters.

In the coming decades, rising sea levels are expected to put 10 million more people at risk of flooding, forcing millions to leave their homes and become climate refugees.Droughts & Famines

Increased temperatures lead to longer and more severe droughts. Researchers found that without efforts to reduce emissions, yields of vegetables would be cut by about 35 percent in the second half of this century.

Crops lost to insects will also increase. When temperatures are higher, the body temperature of insects is also higher, leading to increased energy demands. The result is more insects consuming more food. Two degrees of global warming could double the volume of wheat that is currently lost to pests.

What all of this results in is higher food prices, less stable food supply, and general food insecurity.

Dangerous Heatwaves

The world’s increasing temperatures will lead to longer and hotter heatwaves.

Heatwaves are deadly. Dehydration and heat stroke are common heat-related fatalities, and heat can exacerbate many underlying conditions. The 2003 European heatwave was estimated to have led to the death of 70 000 people – and that was less than 1°C of warming.

Devastating Wildfires

Increased temperatures cause drier conditions, which lead to an increase in wildfires.

Wildfires are extremely destructive of land, human life, and wildlife. Increased fire risk is especially true in the western and northern parts of North America. The USDA Forest Service says just one degree of annual temperature anomaly, which we’re already approaching today, has led to a 600% increase in median annual burned area in some forest types, and is a significant cause of the annual wildfire season having extended over two months in duration longer than average.

Spread of Illness Vectors

As temperatures and waters rise, disease-carrying ticks and mosquitos will thrive in the hot and humid climates.

Vector borne illnesses, such as malaria, Zika virus, Lyme, and West Nile Virus are already increasing. In the past 13 years, mosquito and tick borne diseases have increased threefold in the US. By 2050, it’s estimated that 68% of California’s populations will be at an increased risk for West Nile Virus with current climate change patterns.

Source: EarthStrike