For millions of years, Arctic sea ice has expanded and shrunk in a rhythmic dance with the summer sun. Humans evolved in this icy world, and civilization relied on it for climatic, ecological and political stability. But now the world comes ever closer to a future without ice. The National Snow and Ice Data Center reported that 2019’s minimum arctic sea ice extent was the second lowest on record. Arctic summers could become mostly ice-free in 30 years, and possibly sooner if current trends continue. As the northern sea ice declines, the world must unite to preserve what remains of the Arctic.

Although most people have never seen the sea ice, its effects are never far away. By reflecting sunlight, Arctic ice acts as Earth’s air conditioner. Once dark water replaces brilliant ice, Earth could warm substantially, equivalent to the warming caused by the additional release of a trillion tons of carbon dioxide (CO₂) into the atmosphere and declining sea ice threatens wildlife, from the polar bear to algae that grow beneath the sea ice, supporting the large amount of marine life.

To avoid the consequences the scientific community should advocate not just for lowering greenhouse gas emissions, but also for protecting the Arctic from exploitation. The Antarctic shows the way. In the 1950s, countries raced to claim the Antarctic continent for resources and military installations. Enter the scientists. The 1957-1958 International Geophysical Year brought together scientists from competing countries to study Antarctica, and countries temporarily suspended their territorial disputes (争议). In 1959, 12 countries signed the Antarctic Treaty to preserve the continent for peaceful scientific discovery rather than territorial and military gain.

Sixty years later, we must now save the Arctic. A new Marine Arctic Peace Sanctuary (MAPS) Treaty would protect the Arctic Ocean as a scientific preserve for peaceful purposes only. Similar to Antarctica, MAPS would prohibit resource exploitation, commercial fishing and shipping, and military exercises. So far, only 2 non-Arctic countries have signed MAPS; 97 more need to sign on to enact it into law. Scientists can help—just as they did for the Antarctic—by giving statements of support, asking scientific organizations to endorse (支持) the treaty, communicating the importance of protecting the arctic to the public and policy-makers, and above all, by convincing national leaders to sign the treaty. In particular, Arctic nations must agree that recognizing the arctic as an international preserve is better than fighting over it. In 2018, these countries successfully negotiated a 16-year moratorium on commercial fishing in the Arctic high seas, demonstrating that such agreements are possible.

Humans have only ever lived in a world topped by ice. Can we now work together to protect Arctic ecosystems, keep the northern peace, and allow the sea ice to return?

The first Earth Day took place on April 22,1970. Twenty million Americans, about 10% of the US’s population then, demonstrated(示威) against the widespread attitude at the time of ignoring environmental issues. Now, 50 years later, Earth Day remains an important event to draw attention to necessary actions to protect the planet. Unfortunately, threats to the environment also continue, including at least one that certainly wasn’t as apparent in 1970.

The first Earth Day, notes EDN (Earth Day Network, the global organizer of Earth Day), caused a wave of action, including the passage of landmark environmental laws in the United States such as the Clean Air, Clean Water and Endangered Species Acts, as well as the creation of the Environmental Protection Agency (EPA). Many countries soon adopted similar laws, it adds.

Today, EDN works with more than 75,000 partners in over 190 countries. The theme of 2020 Earth Day is climate action.Thanks to groups like EDN, public awareness and demands for better environmental management have grown dramatically and prompted great progress is many areas.

One problem that hadn’t surfaced much in 1970- the harm of unwanted plastics -has become a major environmental issue. It is drawing increasing attention and is stimulating efforts both to find productive uses for the waste materials and to develop more environmentally friendly alternatives.

Among the recent coronavirus global pandemic (流行病), EDN marked the 50th anniversary of Earth Day with the first Digital Earth Day, a global digital mobilization (动员) on April 22 to address the most urgent threats to people and the planet.

“At Earth Day Network, health and safety of volunteers and participants in Earth Day events are our top concern. Among the recent outbreak, we encourage people to rise up but to do so safely and responsibly-in many cases, that means using our voices to drive action online rather than in person,” said Kathleen Rogers, President of Earth Day Network.

In recent years some extreme weather events have arisen from global warming because of human activities, with studies indicating an increasing threat from extreme weather in the future. Scientists were certain that global warming is being caused mostly by increasing concentrations of greenhouse gases and other human activities.

Its effects include warming global temperature rising sea levels and expansion of deserts in the subtropics (亚热带). Warming is expected to be greater over land than over the oceans and greatest in the Arctic, with the continuing loss of glaciers, permafrost and sea ice. Other likely changes include more frequent extreme weather events including heat waves, droughts, heavy rainfall with floods, heavy snow-fall and species extinction due to great change of temperature. Bad effects on humans include the threat to food security from decreasing crop yields and the loss of populated (住人的) areas because of rising sea levels.

Possible responses to global warming are reduction of emissions (排放), adaptation to its effects, building systems resilient to its effects, and possible future climate engineering Most countries are parties to the United Nations Framework Convention on Climate Change (UNFCCC), whose objective is to prevent dangerous climate change. It has adopted a range of policies designed to reduce greenhouse gas and to assist in adaptation to global warming. It is agreed that future global warming should be limited to below 2.0℃ (3.6°F) relative to the pre-industrial level.

On 12 November 2019, NASA scientists reported that human-made carbon dioxide continues to increase above levels that have not been seen in hundreds of thousands of years: currently, about half of the carbon dioxide released from the burning of fossil fuels remains in the atmosphere and is not absorbed by vegetation and the oceans.