MIAMI (BLOOMBERG) - Extreme temperatures in China coupled with a lack of hydro-power forced blackouts in some of its largest industrial cities last month (June).

A rare and short-lived subtropical storm popped up in the South Atlantic off Argentina and Uruguay. And record heat continues to sear Canada and the Pacific North-west, while drought crackled the entire western United States, leaving it primed to burn.

Summer in the Northern Hemisphere is just days old, but the extremes keep piling up.

The conditions driving these events - heat, ocean warming, changes in longstanding weather patterns - are not going away anytime soon, meaning the worst may be yet to come.

While forecasters have known for weeks that this summer was going to brutal, that has done nothing to lessen the shock as the records and casualties mount.

More than 60 people have died during the current heat wave in Oregon, and more than 300 have perished in British Columbia.

"It's just a matter of running up the score, at this point," said Dr Judah Cohen, director of seasonal forecasting at Atmospheric and Environmental Research, part of risk analytics firm Verisk.

The US has led the world in economic losses from climate-related disasters, which totalled US$944.8 billion (S$1.27 trillion) from 1998 to 2017.

China was second with US$492.2 billion and Japan third with US$376.3 billion, according to the United Nations Office for Disaster Risk Reduction.

Extreme weather cost America US$45.4 billion per year on average from 1980 to this year, according to the National Centres for Environmental Information. There were nearly two-dozen US$1 billion disasters last year that killed 262 people and cost a total of US$96.4 billion, the fourth most ever. And the frequency of such events is rising.

The culprit behind these events is increasingly clear and obvious: climate change.

In the case of a tornado that ripped across the Czech Republic last week, for instance, a cold and wet spring followed by record June heat transferred latent energy into the atmosphere that resulted in the extreme weather.

Scientists at Austria's Central Institute for Meteorology and Geodynamics said hotter temperatures caused by climate change were to blame.

The storm left five dead. Even as much of the world is suffering, the US stands to be pummelled especially hard by severe weather and the fluctuations of a changing climate.

A warm pool in the North Pacific is creating a ridge of high pressure that is bending the jet stream and its wet winter storms away from California, leaving the South-west dry, said Dr Jennifer Francis, a senior scientist with the Woodwell Climate Research Centre.

Missing Arctic sea ice due to climate change could well be fuelling that ridge. The entire mechanism got a boost this year because there was a La Nina in the Pacific, which tends to favour a drier California and West.

"Losing ice in this area allows the ocean to absorb extra heat during the summer, which is released into the atmosphere during fall and winter," Dr Francis said in a March interview. "That extra heat is what beefs up the ridge that fuels the drought."

Across 11 western states, more than 98 per cent of the land is abnormally dry, and drought has taken hold across more than 93 per cent, according to the US Drought Monitor.

Conditions are so dry, the wildfire threat has arrived in many places a month early, US Department of Agriculture forecaster Gina Palma said last month.

The threat is forecast to be above normal from the Pacific North-west down the Rocky Mountains in the east and the coastal and Sierra Nevada ranges in California come this month, according to the National Interagency Fire Centre.

Next month, that danger zone will spread across Montana and into North Dakota and South Dakota. This comes a year after record fires charred California and Colorado. Until June 29, more than 30,000 wildfires had sparked this year across the US, up 25 per cent from this point last year.

The Atlantic hurricane season has already begun on the opposite side of the country, from the Gulf of Mexico to the Gulf of Maine, people are grappling with what will be another over-active hurricane season.

The same goes for populations in the Caribbean, Central America and Canada. While this year is not forecast to reach the 30-storm record of 2020, the season will likely produce more than the 14-system average. Five have already spun up in the Atlantic.

"This season is off to a fast start," said Dr Phil Klotzbach, lead author of the Colorado State University seasonal hurricane forecast. "While in general, early season activity isn't much of a harbinger of what may come later in the season, if we get storms forming in the eastern and central tropical Atlantic prior to August, that is typically a harbinger of a very active season."

On Thursday, Tropical Storm Elsa formed about 1,100km east of the Windward Islands, which include the nations Dominica, Grenada, and Martinique - exactly in Dr Klotzbach's area of concern.

The storm strengthened into a hurricane and on Friday, Elsa blew roofs off homes, toppled trees and sparked flooding in the island nation of Barbados, then pounded St Vincent with heavy rain and winds. Elsa is tracking towards Haiti.

Overall, water temperatures in the Atlantic are above average and typical of what you would see in an active year, Dr Klotzbach said.

Many parts of the Caribbean, Central America and the US are still trying to recover from past hurricane seasons. Louisiana, and Honduras and Nicaragua, were all hit by back-to-back hurricanes last year, with hurricanes Iota and Eta leaving hundreds dead in Central America. The storms caused US$3 billion in damage to Honduras, Guatemala and Nicaragua, according to UN and government estimates.

"Climate change is compounding the misery of people living in these vulnerable communities," Mr Tom Cotter, director of emergency response and preparedness at Project Hope, a Virginia-based humanitarian organisation, said in an interview in May.

Temperatures may run above normal in much of the western and northern US, across eastern Europe and into the Middle East to next month, according to the forecast by Columbia University's International Research Institute for Climate and Society. But the biggest deviations towards warming will be in Greenland and along Russia's Arctic Ocean coastline, a trend long seen by scientists.

That warmth at the Arctic coast is a problem, Dr Cohen said. Research indicates the sharp divide in temperatures between the Arctic Ocean, which still retains some of its ice, and the very warm shoreline.

Because the far north is so warm, the contrast between temperatures there and at the equator is less than it used to be, which weakens the weather patterns. In between the pole and the equator is "no man's land, so these heat domes get trapped in between", Dr Cohen said.

Heat domes are mountains of high pressure that bring extreme temperatures. It was a heat dome that baked Portland, causing it to break its all-time temperature record three days in a row. In Canada, Lytton Area in British Columbia posted the nation's highest temperatures ever on Sunday, Monday, and Tuesday. The final mark reached 49 deg C - warmer than Dallas, Texas, has ever been.

"It's mind-boggling," said Dr Daniel Swain, a climate scientist at the University of California Los Angeles. "And I say that as a meteorologist, as well as a climate scientist. It is incredible to see these particular places get so hot on so many consecutive days."

It is not just Canada and the US that have cooked in the last few weeks. Moscow posted its warmest June day since the time of Czar Nicholas II.

Taiwan faces its worst drought as well, which drove up food prices and threatened chip makers. The United Arab Emirates sweltered through a high of 52 deg C, only to be bested by a 53 deg C reading in California's Death Valley two weeks ago. And another heat dome is baking the Caspian Sea, where records are expected to fall.

The harmful effects of heat take many forms Ms Kimberly McMahon, public weather services program manager for the US National Weather Service, calls heat "the silent killer. It is not something visual like a tornado or a hurricane".

Even when it does not kill, it makes life significantly harder. Power lines cannot transmit as much electricity in extremely hot conditions. Airplanes cannot carry as much weight because the air is less dense. Roads buckle as happened in Oregon and Washington this week, Ms McMahon said.

While there is not a completed investigation into the Pacific North-west heat dome's provenance, climate change is its likely parent.

"Without human-induced climate change, it would have been almost impossible to hit such record-breaking mean June temperatures in the western United States," said Dr Nikos Christidis, a climate scientist with Britain's Met Office.

"The chances of natural occurrence is once in every tens of thousands of years."